Alistair Darling’s tax give-away on Tuesday offered a partial solution to compensating the losers from the abolition of the 10p rate – but left him with several awkward questions to answer in the pre-Budget report.

The chancellor must return to the Commons in November and tell MPs whether the rise in income tax allowances is permanent or set to be taken away and whether the £2.7bn cost will breach the government’s borrowing rules.