The Conservatives have positioned themselves as the natural heirs to Tony Blair, pledging to continue the Labour leader's reforms of hospitals and schools.
The increasingly centrist Tory party are using Mr Blair's departure to warn of a "lurch to the left" in the Labour party.
Speaking in London, the shadow chancellor George Osborn pointed to the leftist ethos of the deputy candidates - with Hilary Benn stepping off message to describe himself as a socialist.
Predicting that a Brownite government would be a "roadblock to further reform," Mr Osborn told the Policy Exchange think tank there was a growing consensus between Mr Blair and the Conservative party.
He said: "As the Prime Minister leaves office, there is agreement between him and ourselves on the essentials of the way forward - if not on the methods of achieving it.
"We both agree that the country needs taxpayer funded public services that are free at the point of access, and which are exposed to consumer choice. And we also both agree that this choice should include, with certain proscriptions, the ability to receive that service from an alternative provider.
"This growing consensus between the current prime minister and the Conservative party does not appear to include the next prime minister. And therein lies the political battle ahead. For Gordon Brown rejects the very idea that there should be alternative providers of taxpayer funded public services."
Mr Osborn questioned Mr Brown's commitment to public service reform, claiming the chancellor lacks vision.
Momentum would not come from his deputy, Mr Osborn continued, claiming the deputy candidates represent an "abandonment" of the centre ground within the Labour party.
Mr Osborn continued: "The unreconstructed elements of the left have always opposed reform of the public services. The difference now is that the people around Gordon Brown are also making the case against choice and diversity - and challenging the key elements of the Blair settlement."
Insisting the Conservatives are the true heirs to Mr Blair, he said: "Gordon Brown's plans for public services are like giving citizens of East Germany a greater say in the colour of the Trabant they want to buy.
"It's not a real voice because it is not a real choice.
Sidestepping the potential irony, he justified the Conservatives' plan to assimilate New Labour's policy and reject its traditional policies.
He did claim David Cameron would pursue a different approach to the outgoing prime minister. He said Mr Blair had alienated professionals in pushing through reforms, while the Tories would be less reliant on central targets and top-down control.
Mr Cameron has previously downplayed the suggestion he is the "heir to Blair", but the shadow chancellor's keynote speech indicated the Conservatives have become more comfortable in embracing the centre ground.
It follows a prolonged struggle between the party's modernising and traditional wings over the Tories' traditional commitment to grammar schools.
Mr Cameron has said a Conservative government would continue Mr Blair's commitment to city academies rather than pushing for a return to grammar schools and the 11 plus. This was greeted angrily by his grassroots support, who the Conservative leader went on to blast as "naive".
Yesterday, the Tory European shadow minister Graham Brady resigned from the frontbench after clashing with the Conservative leadership over grammar schools.