The Tories are in favour of marriage and want more of us to get hitched. At least, I assume that's why they're offering a tax break for married couples worth £150 a year.

But don't be rushing to the altar just yet. According to the Daily Mail, which doubtless spends more time thinking about these matters than I do, the average wedding today comes in at £20,273. By my calculations, that means that - under the Tory proposals - marriage doesn't start to pay off until after you've celebrated your 135th wedding anniversary.

Now that's what I call a long-term investment.