Whitehall officials modelled several plausible scenarios — and Chancellor Philip Hammond said the UK would be worse off post-Brexit "if you look at this purely from an economic point of view" — although no scenario followed the deal Prime Minister Theresa May agreed with EU officials. The Chequers scenario — with 50 percent higher non-tariff barriers — concluded GDP would be 2.1 percent lower in 2035/36.
The Norway EEA scenario, favoured in some quarters, would see GDP contract by 1.4 percent in 15 years' time, while under a Canada-style deal, advocated by Boris Johnson and David Davis, the UK would be 4.9 percent worse off.
A regional breakdown showedthe north-east of England would be worst affected by leaving the EU in a no-deal scenario, followed by the West Midlands, the North-West and Northern Ireland. In the best-case scenario, London and the south-east would be the worst affected, although the overall GDP impact would be lower. Scotland, Wales and Northern Ireland would be least affected.