George Osborne will begin a counter-offensive against Labour today with a personal attack on Gordon Brown as the Tories seek to prove that they are ready for an early election.

The Conservatives are preparing an advertising campaign to run through next month to back up what is being called a “Summer Heat on Brown” campaign.

The Shadow Chancellor will say in a speech in Liverpool that the Tories plan to attack the new Prime Minister on his record on youth unemployment, welfare and poverty. Promising to “shine a light on Gordon Brown’s broken society”, Mr Osborne will say that the cost of social failure is the equivalent of an annual bill of £4,000 for every family in Britain. He is expected to say: “We are going to reveal how Brown’s welfare policies have created a hidden iceberg of unemployment, with 5 million people of working age – over one in ten adults – out of work and on benefits.

“We are going to show how Brown’s youth employment policies mean that there are now over a million young people not in work, education or training: more than in 1997. We are going to expose how Brown’s poverty policies mean that the poorest in our society have got poorer.” He will add: “The Prime Minister will not be able to run from his record.”

The speech brings to an abrupt end a period in which the Conservative leadership has avoided attacking Mr Brown head-on. Mr Cameron was recently warned by internal pollsters that such attacks during the new administration’s first few weeks would rebound on him.

He has decided, however, that taunts from Labour that it is preparing to fight a snap election this autumn cannot go unanswered. A senior figure told The Times: “This is partly about gearing up the party but also about showing that we have the money and material to fight.”

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