Shadow boxer

He is not impressed. "This is old Labour; it's tax and spend," he says. "It's a dangerous gamble with the economy. It looks like economic stimulus, but it could drive down demand and raise inflation."

Key, 57, is the Tory construction spokesman. His job is to shadow construction minister Brian Wilson and attack Labour policy. A free marketeer, he believes the government's preference for public spending over private initiative is potentially disastrous. He is also critical of the strings attached to Brown's billions.

"Construction firms will be hit by the rise in national insurance next April, and so will all their clients. And a hell of a lot of the new money will be spent on the salaries and offices of regulators," he says, referring to the legions of officials that will be required to ensure local authorities are spending their extra money wisely. "With every spending pledge came another tier of regulation and another army of inspectors."

Even if Brown's largesse does produce extra work for contractors, Key does not believe such spending splurges are in the industry's long-term interest: "Like all industries, construction wants to have predictability and stability of orders." He claims Labour governments undermine the industry by beefing up public building and infrastructure programmes when the economy is weak, thus exacerbating the boom and bust cycle. He calls it "the old Keynesian solution – pumping money into construction when the rest of the economy's going downhill".

Key is at ease dissecting the government's economic policies. He read economics at Cambridge, and taught the subject at Harrow for 14 years before becoming an MP in 1983, aged 38. His first government post was construction minister at the then Department of the Environment, from 1990 to 1992. Subsequent ministerial posts at national heritage and transport were followed by a four-year spell as opposition defence spokesman. Last September, Tory leader Iain Duncan Smith appointed him to shadow Brian Wilson. In his 80-hour week he finds time to make contact with construction executives as well as the civil servants, journalists, fellow politicians and constituents who clog his diary.

Despite his two decades in parliament, Key is a country boy at heart. His Wiltshire constituency includes a clutch of villages as well as the cathedral city of Salisbury, where he grew up, and he lists "country life" among his hobbies in Who's Who. He is a big man and, as politicians go, pretty affable and easygoing – more Ken Clarke than Michael Howard.

This is old Labour; it’s tax and spend. It’s a dangerous gamble with the economy

Although his main job is to attack government policy on construction, Key is careful to play the ball and not the man. "Brian Wilson and I get on fine, although we come from opposite ends of the political spectrum," he says. "I first knew him as an angry young Marxist newspaper editor on the west coast of Scotland." He praises Wilson as a hard-working minister, but feels his twin responsibilities for energy and construction mean he isn't devoting enough time to either.

The positive side of the dual brief is that Key is very clued up on sustainability issues. He describes Labour's environmental policy as "muddled" and says: "We need far higher standards of insulation in our buildings, and we should look at different heating and cooling strategies, paying far more attention to geothermal energy systems and heat pumps." But the tax-resistant Tory spokesman disapproves of the aggregates levy and climate change levy, arguing that both hurt the construction industry.

Key is also scathing of the government's handling of the skills shortage. He believes schools and universities should be promoting construction careers at grassroots level. "This is another thing I'd like to see the construction minister's team doing. At the moment they say, 'it's nothing to do with me, guv, that's down to the education people'."

Despite the Labour administration's proclaimed belief in joined-up government, Key says interdepartmental buck-passing is common. A series of Whitehall shake-ups means that, although the construction directorate moved to the DTI in 2001, building regulations now come out of John Prescott's new Office of the Deputy Prime Minister. Betraying a rose-tinted view of John Major's government, Key says: "Construction was very well treated when I was at the Department of the Environment, because all the legislation was coming out of the same ministry."

Since Stephen Byers' departure prompted yet another reshuffle in May, Prescott has also inherited the housing and regeneration briefs. Key won't be drawn on whether he supports affordable housing quotas for new developments, but he says he sympathises with housebuilders struggling against restrictive planning rules.

Prescott, who has an extra £1.5bn as a result of the spending review, is pledging to build 200,000 new homes over the next 10 years. Key believes the way to solve the housing shortage is to "stop subsidising bricks and mortar and start subsidising people".