Stamp Duty Land Tax on residential property

SDLT is charged progressively, like Income Tax, not as a flat percentage of the whole price: each band's rate applies only to the slice of the purchase price within that band, not to the entire amount. Applying the top rate reached to the whole price is a leftover from the pre-2014 'slab' system, which was scrapped precisely because it created sharp cliff-edges at band boundaries. An additional-property surcharge of 3% is added on top of the standard bands for anyone buying a residential property while already owning another one — charged on the whole purchase price, not just the amount above a threshold. First-time buyers get a separate relief instead: no duty at all up to the relief limit, and a reduced rate on the excess above it — but that relief doesn't mean first-time buyers never pay anything; above the limit, duty is still due, just calculated differently.