David Cameron turns brickie for the day

In hard hat, hi-vis vest and wielding a trowel, the prime minister turned brickie today on a building site in Chorley - the same Lancashire town Ed Miliband visited on Monday.

He insisted that this was not the first time he'd laid bricks before, joking to the professionals that he was a bit worried he was "the weak link in the chain".

The choices of destinations and photo opportunities tell you a good deal about the men fighting to hold the keys to Number 10 after the next election. The North West is one of the key battlegrounds in that contest. Lancashire is a key Labour target in next week's county council elections.

Where Ed Miliband's soap box speech in Chorley market was clearly designed to counter the oft-repeated charge that he's unable to connect with ordinary people (the so-called "weird" factor) David Cameron was, no doubt, trying to prove that he too is not out of touch (the so-called "toff" factor).

The prime minister was also promoting the government's new Help to Buy scheme, which subsidises mortgages for those with small deposits. He argues that the government is stepping in to fill a gap left by the banks - who are demanding historically high deposits from people who would normally have no difficulty buying a home.

This scheme is loved by the housebuilders, who helped design it. Half the 120 or so homes which Barratts expect to sell this year on their new estate in Chorley are likely to receive a government subsidy.

Help to Buy is not, though, without its critics. The all-party Treasury Select Committee has demanded to know why the government is, in effect, propping up house prices.

They have also asked the government to explain how it will ever be able to stop supporting homeowners once they've started and how they'll avoid subsidising second home owners. Others focus on questions of fairness. Why should someone able to buy a home worth up to £600,000 get a taxpayer subsidy when those renting and dependent on housing benefit are facing cuts?

Whatever the rights and wrongs economically David Cameron knows that home building is one of the most potent images in British politics. Tory Prime Minister Harold Macmillan promised to build 300,000 homes; Margaret Thatcher sold people their council houses and, as David Cameron told his fellow brickies on a roof in Chorley on Friday, Winston Churchill used to lay bricks as a form of relaxation.

PS I'll be putting some of these concerns to David Cameron in an interview later.