101 Things to Know About UK Immigration Law
— by Michelle Lee, UK immigration solicitor.
I’ve spent years helping people navigate the UK’s immigration system. It’s messy, complicated, and constantly changing.
Here are 101 things worth knowing, whether you’re applying yourself, employing someone from overseas, or just trying to make sense of a system which remains surprisingly easy to get wrong.
The Basics
1. Most of the UK’s immigration system lives in the Immigration Rules, not legislation, which means the government can change the rules without an Act of Parliament. They do, all the time.
2. There are two types of permission to be in the UK: leave to enter and leave to remain. Leave to enter gets you onto UK soil; leave to remain lets you stay once that permission runs out.
3. Section 3C leave is a safety net. If your visa expires while a decision is pending you’re still legally in the UK, as long as you applied before your visa expired.
4. Leaving the UK while your application is pending automatically withdraws it and cancels your 3C leave too. Don’t travel without taking advice first; you might not get back in.
5. A refusal won’t automatically count against you in future applications, unless deception or dishonesty was involved.
6. Since February 2025, anyone who has ever entered the UK illegally will normally face a lifetime ban on ever getting British citizenship. No exceptions for time passed.
7. Visa holders contribute to the cost of NHS access through the Immigration Health Surcharge, and it’s not a small amount.
8. Submitting your application doesn’t send it to the Home Office straight away. It only reaches them once your biometrics are in too, either via the UK Immigration: ID Check app, or at an in-person appointment.
9. Biometrics appointments aren’t run by the government. They’re handled by private companies: VFS Global or TLS Contact, on behalf of the Home Office. The appointment is quick and involves having fingerprints and a passport-style photo taken.
10. Most immigration applications don’t require an interview. Asylum is the main exception.
11. eVisas have now replaced Biometric Residence Permits as proof of immigration status. Your status now lives online, and you need an account to view it.
12. If your application is refused, your fee won’t be refunded. The most you can hope to recover is the Immigration Health Surcharge.
13. The right of appeal is limited to applications that engage your human rights. Other refusals may carry the option of Administrative Review or a reconsideration request instead, which is essentially asking the Home Office to check its own decision.
Fees
14. Most time-limited visas come with two fees: the application fee and the Immigration Health Surcharge (IHS). Added together, and across multiple renewals on the way to settlement, the costs really mount up.
15. ILR and citizenship are the exception as there’s no IHS payable, just the one application fee in each case.
16. That said, ILR is one of the most expensive single applications in the system.
17. In-country fees tend to be slightly cheaper than overseas fees, but for most people, where they apply from is determined by where they are in the visa journey, not personal preference.
18. Fees apply per person, so a family application with adult and child dependants can run to a significant sum of money.
19. Priority and super-priority services are available for some applications. The additional fees can be steep, but when you need a faster decision it can be well worth it.
20. Fee waivers exist for some human rights-based applications, but they’re not easy to secure and require substantial financial evidence.
21. Getting it wrong is expensive. Fees aren’t refunded following a refusal (except the IHS), so reapplying means paying again in full.
22. Fees are reviewed by the Home Office at least once a year. It’s rarely good news for applicants.
Life in the UK Test and English Language Requirements
23. The Life in the UK Test is required for ILR and citizenship, but not for visa applications.
24. A Life in the UK Test pass never expires. The system changed in 2019, but that only affects how you prove your pass. Pre-2019 pass certificates are still valid for use.
25. If you fail the Life in the UK Test, you can resit it as many times as you need. The Home Office won’t know how many attempts it took. The only real drawback is paying the fee each time.
26. The simplest way to meet the English language requirement is to be a citizen of a majority English speaking country.
27. Majority English speaking countries are largely what you'd expect: Australia, the USA, Canada, New Zealand, and many Caribbean nations. One notable exception is South Africa, which is not on the list.
28. You can also meet the requirement by holding a UK degree, an overseas degree taught in English, or by passing an approved English language test.
29. The level required, and which components are tested, depends on your visa route. Skilled Workers need to pass at a higher level across all four components (speaking, listening, reading and writing). Family routes require a lower level in speaking and listening only.
30. Any English language test must be from an approved provider at an approved test centre. These are listed on the Home Office website and can be found worldwide, including within the UK.
31. Finding, booking and passing the right test is the applicant’s responsibility, and it’s not always straightforward. Providers offer a lot of options, not all of which are suitable for every immigration route. If in doubt, take advice.
Visitors
32. Visitors fall into two categories: visa nationals, who need a Visitor visa, and non-visa nationals, who just need an ETA.
33. A Visitor visa is just that: for visiting. You must leave at the end of your trip, and switching to another visa route from inside the UK is almost impossible.
34. Visitors cannot work in the UK. There are a handful of exceptions, narrowly defined.
35. Visitor visa applications can be surprisingly difficult to get approved. The Home Office takes a strict approach and refusals can come down to very minor reasons. Legal advice is becoming increasingly necessary. Even though the visa fee itself is relatively low, it’s worth budgeting for professional help too.
Partner Visas
36. You can apply for a partner visa as a fiancé(e), spouse, civil partner, or unmarried partner.
37. The requirements are exactly the same for same-sex and heterosexual couples.
38. The non-applicant partner doesn’t have to be British. They can also be an ILR holder, someone with settled or pre-settled status, or a person in the UK with refugee protection status.
39. A fiancé(e) visa lasts six months. In that time, you must marry or form a civil partnership, then apply to switch to a spouse visa.
40. The fiancé(e) visa doesn’t include the right to work. That comes later, with the spouse visa.
41. The Marriage Visitor visa is just for the wedding. It doesn’t let you stay in the UK afterwards.
42. Partner visas, with the exception of the six-month fiancé(e) visa, are granted for 2.5 years. You can apply to extend within the 28 days before your expiry date.
43. An entry clearance partner visa is technically granted for 2.5 years plus three months. The extra three months is designed to give you time to travel to the UK, but it does result in an uplift to the total IHS you need to pay.
44. Partner visa couples must have met in person and the relationship must be genuine (real) and subsisting (ongoing). A relationship on paper isn’t enough.
45. Entering into a sham marriage to obtain a visa is a criminal offence. People have served jail time for it.
46. Lots of different documents can evidence a genuine relationship: a marriage certificate, proof of living together, photos, messages, trips taken together, statements from the couple and family and friends.
47. Not all relationship evidence is created equal. A marriage certificate and solid cohabitation evidence will always count for more than photos and messages alone.
48. The financial requirement is the most complicated part of a partner visa application. It's designed to ensure that the couple can support themselves in the UK without relying on the welfare system.
49. Alongside the financial requirement sits the accommodation requirement: the couple and their family must have adequate accommodation that isn't overcrowded.
50. The financial requirement can be met in a number of ways: employment or self-employment income, savings, pensions, dividends, rental income, and more. But promises of third party support are not normally accepted.
51. For the first application, only the partner's income counts and the applicant's own income can't be used. That changes at extension stage, when the applicant's income can be brought in alongside or instead of the partner's.
52. If your partner receives certain benefits, such as Disability Living Allowance, Carer's Allowance, or Personal Independence Payment, a different financial threshold applies, known as adequate maintenance and accommodation.
53. Suitability requirements for partner visa applications were recently tightened under what's known as Part Suitability.
Skilled Workers
54. Salary thresholds for sponsored work visas have become increasingly complicated, with multiple rounds of changes in recent years. The minimum you need to be paid depends on your job role, when your sponsorship began, and other factors. It’s rarely a one-size-fits-all figure.
55. Your employer can issue your CoS for anywhere up to five years. In practice, two or three years is most common.
56. The new entrant rate can make a real difference to your chances of being sponsored. It reduces the salary thresholds; both the general minimum and the going rate for your role. Your salary will need to increase once you gain more experience, but that’s what makes it a win-win for both sides.
57. You qualify as a new entrant if you’re under 26 on the date of your visa application, or if you’re a recent Student or Graduate visa holder.
58. New entrant status only lasts for up to four years in total, and any time spent on the Graduate visa counts towards that limit.
59. Supplementary employment outside your CoS is possible, but the conditions are strict. Tread carefully and take advice.
60. Employers are not permitted to pass on the costs of sponsorship to their workers. Any employer trying to do so should be a red flag.
61. If your employer loses their sponsor licence, your permission to stay will be cancelled to 60 days. In that time, you’ll need to find an alternative basis to remain and submit a new application, or leave the UK. You can continue working for your sponsor during the 60-day cancellation period.
Sponsor Licences
62. Applying for a sponsor licence requires evidence about your business. For established employers this is usually straightforward, but newer businesses may need to work a bit harder to demonstrate legitimacy.
63. Every sponsor licence application must nominate three Key Personnel: an Authorising Officer, a Level 1 User, and a Key Contact. All three roles can be held by the same person, or split between different people.
64. The Authorising Officer is your most senior person responsible for recruitment. The Level 1 User manages the licence day-to-day. The Key Contact is who the Home Office will come to with queries.
65. The application form is completed online but that’s not the end of it. Supporting evidence and a submission sheet must then be sent by follow-up email within five working days.
66. The standard processing time for a sponsor licence is eight weeks.
67. Priority service is available and can bring that down to ten working days, but it’s not guaranteed. You need to request it (and pay the fee if successful) when you submit the application.
68. Compliance isn’t something you can think about later. The Home Office can inspect from the moment you submit your application, and at any point during the life of the licence.
69. Most compliance duties are common sense: keeping employee records, maintaining up to date contact details, conducting right to work checks, and similar. There are also reporting duties: certain events affecting sponsored workers must be reported to the Home Office within set timeframes.
70. If the Home Office believes you’ve fallen short on compliance, they can downgrade, suspend, or revoke your licence. The disruption to your business can be significant.
71. There is usually some scope to challenge enforcement action taken against your licence, but the timeframes are tight. Don’t sit on it – take advice immediately.
72. If your licence is revoked, your sponsored workers’ permission to stay will be curtailed to 60 days. They can continue working for you during that period but the clock is ticking.
73. Once your licence is granted, your Level 1 Users get access to the Sponsor Management System (SMS), the online portal used to manage the licence. SMS login details must not be shared with anyone, even colleagues or the Authorising Officer if separate to the Level 1 User. Doing so is a specific ground for revocation.
74. A Certificate of Sponsorship (CoS) is a virtual document generated on the SMS. You need one for every worker you sponsor.
75. A sponsor licence and a CoS are two very different things. The licence belongs to the business and gives you the ability to sponsor; a CoS is the means by which a worker is actually sponsored.
76. There are two types of CoS: Defined (DCoS) and Undefined (UCoS). Assigning the wrong type, even by mistake, is a specific ground for licence revocation.
77. Use a DCoS if your worker is applying for their visa from overseas; use a UCoS if they’re applying from within the UK. Both cost the same.
78. UCoS are subject to an annual allocation, applied for as part of your licence application. DCoS are issued on an as-needed basis once the licence is granted.
79. Your first DCoS application can take up to six weeks. After that, subsequent requests can come back in a day or two, unless the Home Office wants more information.
80. Salary thresholds for sponsorship have become one of the most complicated areas of the system, with layer upon layer of changes made by successive governments. What you need to pay a sponsored worker depends on the job role, when their first sponsorship began (even with a different employer), and more. Getting this wrong can cost you more than the PAYE figure. If you’re in any doubt, take advice before assigning the CoS.
81. The new entrant rate is well worth knowing about as a sponsor. It reduces the salary you need to pay, which can be particularly helpful for smaller businesses or junior roles. It applies most commonly where the worker is under 26 at the date of their visa application, or holds a recent Student or Graduate visa.
82. New entrant status has a four-year limit, and any time your worker spent on the Graduate visa counts towards that total. Keep track of this, as it affects when their salary will need to increase.
83. You cannot pass the costs of sponsorship on to your workers. This includes application fees and the Immigration Skills Charge. Attempting to do so is a breach of your sponsorship duties.
Settlement
84. Indefinite Leave to Remain (ILR) means what it says: you can live in the UK indefinitely, with no renewals needed.
85. ILR is also called settlement. The terms mean the same thing.
86. Settled status under the EU Settlement Scheme is a special form of ILR, with some unique characteristics. That means all settled status is ILR, but not all ILR is settled status.
87. The EU Settlement Scheme is technically still open, but late applications need to be justified. You’ll need good reasons for the delay, supported by evidence.
88. Most visa routes lead to settlement eventually after a set number of years, with visa renewals along the way to get there.
89. ILR applications come with absences rules, but the exact limits depend on which route you’re on and when your absences happened. It’s not one-rule-fits-all.
90. ILR is hard to lose, but it can happen. The main risks are being absent from the UK for two or more years (five years for settled status), or committing a serious criminal offence.
Citizenship
91. Citizenship applications are governed by the British Nationality Act 1981, one of the few areas of immigration law set out in statute rather than the Immigration Rules.
92. As an adult, the section of the Act you apply under depends on your relationship status: section 6(1) if you’re not married to a Brit, or section 6(2) if you are.
93. Being married to a British citizen comes with advantages, including a shorter qualifying period of three years instead of five.
94. The good character requirement goes further than a clean criminal record. It also includes unpaid taxes, NHS debts, and financial issues like bankruptcy.
95. To qualify for citizenship you must not exceed the absence thresholds, both across the full qualifying period and in the final year before you apply.
96. If you do exceed the thresholds, the Home Office can exercise discretion and overlook it. You’ll need to ask for discretion, explain your circumstances, and back it up with evidence. This is commonly where I’m involved.
97. Once your application is granted, you don’t formally become British until you attend a citizenship ceremony and receive your certificate of naturalisation. That’s when it’s official!
98. A British passport isn't issued automatically. It's a separate application, for which you'll need your naturalisation certificate.
99. The UK has no issue with dual or multiple nationality, but other countries do. Some will even strip you of your original citizenship the moment you become British. If keeping your other citizenship(s) matters to you, check the rules carefully before you apply.
100. A child born in the UK isn’t automatically British, and a child born overseas to a British parent isn’t automatically excluded. There are routes to automatic entitlement and registration, which tend to be simpler and cheaper than waiting until adulthood.
And Finally…
101. Immigration law changes constantly. Always check the current rules before you apply, or use the services of a solicitor who stays on top of it for you!