Patriotism is a fine thing on the battlefield, but a poor basis for investment strategy and, quite possibly, the last refuge of a government about to lose a general election. Jeremy Hunt’s budget speech on Wednesday confirmed that the chancellor wants company retirement funds and Isas to buy more British shares, despite rotten returns lately.

A British Isa might be nicer because it means everyone will be allowed to shelter an extra £5,000 a year tax-free in UK shares and funds, in addition to the existing £20,000 annual allowance. This should help people who have left it late to start investing and want to catch up. Unfortunately it is unclear how British these funds and shares must be. Is a London listing enough, or must