A significant change to the way millions of Britons settle their income tax liabilities is quietly taking shape in Whitehall, and those affected would do well to pay attention now rather than scramble to adjust when April 2029 arrives. The reform targets self-assessment taxpayers — among them the self-employed, sole traders, landlords, and those drawing income from savings or investments — who also receive employment or private pension income taxed through Pay As You Earn (PAYE). For this group, the familiar rhythm of annual lump-sum payments is set to be replaced by something considerably more continuous.
Under the current system, self-assessment filers report their income and settle the tax owed for the previous year by 31 January, with a further payment on account — equivalent to 50 per cent of the prior year’s bill — due by 31 July. The arrangement has long been a fixture of British tax administration, but HMRC now proposes a material departure from it. Those who file self-assessment returns and simultaneously receive income via PAYE would, from April 2029, no longer face those large periodic settlements. Instead, an estimated portion of their tax liability would be collected automatically, either monthly or quarterly, directly through their wages or pension.
The arithmetic is straightforward enough. Taxpayers paid monthly through PAYE would see roughly 8.3 per cent of their projected tax bill deducted each month — spreading what was once a concentrated financial obligation across the full year. HMRC estimates that approximately 2.1 million people fall within the scope of the proposed change, a figure that underscores the breadth of the reform’s reach.
Reconciliation would still take place at year end. Where the monthly collections fall short of the final liability, the outstanding balance would be payable by 31 January 2031 upon filing the relevant tax return. Conversely, where collections overshoot, the government would issue a refund once the return has been processed — a mechanism familiar in principle, if not always swift in practice.
A formal consultation ran from 23 June to 4 August, inviting views on the proposed design of the reforms, the practicalities of collection timing, safeguards for taxpayers, and the support needed to ease the transition. Officials have also signalled an appetite to explore whether more timely payment arrangements might eventually extend to self-assessment taxpayers without any PAYE income at all — a hint that this reform could be the first phase of a broader restructuring of how Britain collects income tax from those outside conventional employment.
The government has committed to publishing its response to the consultation in Autumn 2026, with any necessary legislation to follow in a Finance Bill ahead of the April 2029 implementation date. That timetable offers a reasonable window for preparation, but the complexity of the change — particularly for those whose income fluctuates year to year — means that early engagement with a tax adviser is unlikely to be wasted. The administrative logic of smoothing tax collection is coherent; the practical burden of transition, for many, will be anything but trivial.