Your National Insurance Number: apply only once you're in England, and you can work before it arrives

Yes, you get a National Insurance Number (NIN), and you apply for it only once you're in the United Kingdom — not from the Netherlands. After the identity check it takes up to four weeks. The trap is not in the application but in the waiting: many newcomers think they can't start work without the number. GOV.UK says the opposite: you can start work as soon as you can prove you're allowed to work in the UK, and you do that with your share code, not with your NIN.

What is the number, actually?

The National Insurance Number consists of two letters, six digits and a final letter, in the form QQ123456B. It is for life: even if your personal details change, the number stays the same. It is used to record your contributions and tax against your name, and it will appear on tax documents such as your payslip and your P60, your employer's annual statement.

GOV.UK asks you to handle it sparingly, to prevent identity fraud: only share it with those who really need it. They include HMRC, your employer, the Department for Work and Pensions, the council if you claim Housing Benefit, electoral registration, your pension provider and the provider of an ISA savings account.

When can you apply?

You can apply if you live in the UK, have the right to work there, and are working, looking for work or have a job offer. Earlier is not possible; you can only apply once you're there. Whoever wants to "just sort out the number" from the Netherlands hits a closed door.

One check first: look in your UKVI account. GOV.UK notes that with an eVisa you may already have a National Insurance Number. If it's there, a new application is unnecessary.

How does the application work?

Online. Have your passport ready, or a national identity card from an EU country; you enter details from it. Then you prove your identity with a photo of yourself holding your passport, plus photos of any other documents. A smartphone will do, and someone else may take the photo. If uploading doesn't work, you can still apply, but an in-person appointment or posting copies follows, and it takes longer.

After submitting you get an email with a reference number. Keep it: if it takes longer than four weeks, or you move in the meantime, you call the helpline with that number to hand. The helpline (0800 141 2079) is free and open Monday to Friday, 8am to 5pm.

Can you work without the number?

Yes. You have to prove your right to work before you start with an employer, and if you're not a British or Irish national, you do that with the share code from your UKVI account or with your valid immigration documents. A share code is valid for 90 days, can be reused as often as you like and you can create one whenever you want. The NIN plays no part in that check. You pass the number on to payroll later, so your contributions are recorded in your name.

The NIN does not prove that you may work. Whoever says you can't start without a NIN is wrong, and an employer who only asks for your number is not doing the check properly. Work is allowed; the number follows.

Which other numbers will you come across?

There is no one number for everything, like the Dutch BSN. Besides the NIN and the share code, two more turn up.

The NHS number is ten digits, for example 485 777 3456. You find it in the NHS App, on a letter or prescription from the NHS, or through your GP surgery. You don't need it to use NHS services.

You only get a Unique Taxpayer Reference (UTR) if you have to file a tax return: Self Assessment. It is compulsory for, among others, a self-employed sole trader with more than £1,000 of income. Whoever has untaxed income, such as rent, savings interest, dividends or foreign income, for example from a house kept in the Netherlands, may have to as well. You then tell HMRC by 5 October after the end of the tax year (6 April to 5 April) in which that income arose; whoever tells them later risks a penalty.

Number	Where from	When	What for
National Insurance Number	application via GOV.UK	only once you're in the UK; up to 4 weeks after the identity check	contributions, tax, social security
Share code	you, in your UKVI account	immediately, again and again; valid for 90 days	proving your right to work and to rent
NHS number	the NHS	once you're in the health system	your medical record; not needed for care
Unique Taxpayer Reference	HMRC	after registering for Self Assessment, by 5 October after the tax year	the annual tax return

And the children?

British children normally get the number in the three months before their sixteenth birthday, if a parent ever claimed Child Benefit for them. If your children did not get it that way, they apply online between sixteen and nineteen, and later in the same way as you once they start work.

The order in England is therefore the reverse of what someone from the Netherlands expects: first the share code and the job, then the number, and only after that the tax. How those first weeks continue is covered in the journey at /engeland.

In Vertrekklaar this is phase 5 of 5 of the journey, step 5.3: the same steps, but for your situation — in your order, tickable, and with the deadlines watched. See the whole journey to England or go straight to step 5.3 in the open plan.