The Federation of Small Businesses (FSB) has urged the Government to reconsider plans requiring roughly three million self-assessment taxpayers to make more regular payments from April 2029. The transition would require many self-employed workers to settle liabilities for both the previous and current tax years, effectively bringing forward tax on income they may not yet have earned. The Office for Budget Responsibility estimates the overlap will increase Treasury cash receipts by £17bn in 2029-30, while the measure is also forecast to raise £1.3bn between 2029 and 2030 and £1.8bn two years later through improved compliance and lower tax debt. The FSB says the system does not reflect irregular self-employed earnings and could force hundreds of thousands of business owners to borrow, with some already paying 11pc interest to manage cash flow. The Government says no one will owe more tax and that smaller, more frequent payments will help taxpayers avoid large bills. The dispute comes as the number of self-employed people and sole traders fell 3.7pc, or 157,000, in the year to January 2026.