Before you start

A National Insurance number
PAYE registration through your employer
A Government Gateway account, if you ever need Self Assessment
Records of foreign income and overseas accounts

Step-by-step

1
Check the tax code on your first payslip
PAYE deducts at source, so a wrong code means wrong deductions for months before anyone notices. Your code should not begin with an S — that is the Scottish prefix, and payroll run from a Scottish head office occasionally applies it in error.
Via employerWho: YouFirst payslip
2
Learn the three English bands
A personal allowance, then Basic, Higher from £50,270 and Additional from £125,140. Three bands where Scotland has six, and a materially later Higher rate threshold. The thresholds have been frozen for several years, quietly pulling more people into higher bands as wages rise.
OnlineWho: You
3
Expect a bonus month to look wrong
PAYE annualises: a large one-off bonus is taxed in that month as though you earned it every month, so the deduction can look punitive. It usually corrects itself across the rest of the tax year without any action from you. In Leeds' banking, legal and consulting employers this is a normal annual event and worth understanding before it happens rather than after.
Via employerWho: You
4
Understand the 60% trap above £100,000
The personal allowance is withdrawn by £1 for every £2 earned above £100,000, giving an effective marginal rate of about 60% between £100,000 and £125,140. Bonus-heavy pay makes it easy to cross that line without meaning to. Pension salary sacrifice is the standard response.
OnlineWho: You
5
Check whether you actually need to file Self Assessment
Most employees never do — PAYE handles it. You must register if you are self-employed, have significant untaxed income, or meet one of HMRC's listed triggers. Online returns are due by 31 January following the 5 April year end.
OnlineWho: You
6
Settle your residence position in year one
The Statutory Residence Test determines UK tax residence from days present and connecting factors. The UK abolished the old non-domiciled regime and replaced it with a residence-based system, and the transitional rules are genuinely complex. Take advice in the first year if you have foreign income or assets.
In personWho: You

Documents you’ll need

National Insurance number
P60 — the annual summary from your employer
P45, if you change employer during the year
Bonus and share-scheme paperwork, which payroll will not explain
Government Gateway credentials, for Self Assessment

Things most newcomers don’t know

A bonus month is over-taxed and then corrects itself, which nobody explains.

PAYE treats each month's pay as if it repeated all year, so a February bonus is taxed as though you earn twelve of them. The excess normally washes out over the remaining months of the tax year. In a city where a large share of the professional market is paid partly in bonus, the panicked email to payroll is an annual ritual — and unnecessary.

Source: HMRC — how PAYE works

The 60% band between £100,000 and £125,140 is the biggest hidden rate in the system.

The personal allowance is withdrawn at £1 for every £2 above £100,000, so each extra pound in that range is taxed at the 40% headline rate plus the lost allowance — around 60% in effect. Bonus-heavy Leeds pay packages cross the line without anyone planning to. Model it, and look at salary sacrifice.

Source: GOV.UK — income tax rates and personal allowances

Frozen thresholds are a tax rise nobody voted for.

The personal allowance and the higher-rate threshold have been held flat for several years while wages rose, so each year more people cross into higher bands without any rate changing. The mechanism is called fiscal drag, and it is why your take-home percentage slips slightly each April even without a promotion.

Source: HMRC

The tax year runs 6 April to 5 April, which catches everyone once.

Almost no other country uses these dates. It decides which year your arrival income falls into, when your P60 arrives, and when Self Assessment is due. Newcomers routinely reckon against a calendar year and get their first filing wrong.

Source: HMRC

Common mistakes to avoid

Not checking the PAYE code on the first payslip, especially for a stray Scottish S prefix.
Panicking at the deduction on a bonus month before the annualisation unwinds.
Accepting a package that lands between £100,000 and £125,140 without modelling the 60% band.
Counting the tax year as January to December rather than 6 April to 5 April.
Ignoring National Insurance when estimating take-home pay.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.