From 2015/16, married couples and civil partners can transfer up to £1,000 of their personal allowance to their partner, but only if neither individual pays tax at the 40% rate. It is therefore a modest tax break, worth a maximum of £200 each tax year, but every little helps (as we are often reminded)! The estimate is that over 4 million couples will benefit. Oddly, there is no allowance transfer available where a man and woman are living together but are not married.
It will be interesting if this is still available come 2015/16 which seems a long way off!