David Cameron will try to turn the pressure back on Gordon Brown today with a stinging attack on his “secretive, power-hoarding, controlling” character.

In one of his most personal attacks to date, the Tory leader will lambast the Prime Minister as a “shameless defender of the old elite”. Mocking Mr Brown’s claim to be a reformer, Mr Cameron will dismiss this week’s Commons vote on a referendum on changing the electoral system as a “cynical attempt to save his own skin”.

Mr Cameron’s speech to the University of East London in Beckton today is also part of the wider effort to regain the political initiative amid a diminishing poll lead. He will move from his Commons suite of offices to Conservative campaign headquarters over the next few days to exert a tighter grip over election preparations, The Times has learnt.

Senior Conservatives figures now privately admit that a £400,000 poster campaign last month was not as successful as had been hoped in winning over doubting voters. Insiders say that an internal inquest has strengthened the hand of those, such as George Osborne, who want the party to make specific pledges to Conservative-leaning voters.

Seeking to harness public anger on MPs’ expenses, Mr Cameron will say “there is no chance Gordon Brown will do what is right and put the public interest before his own political interests. He cannot reform the institution because he is the institution: he made it. The character of his Government — secretive, power-hoarding, controlling — is his character”.

He will add: “For the health of our democracy it is now essential that this shameless defender of the old elite goes as soon as possible”.

Mr Cameron’s attack on the Prime Minister’s character follows reports that Mr Brown wept when asked about the death of his daughter, Jennifer, in the course of a television interview to be screened next weekend. The Prime Minister became visibly upset when discussing the death with Piers Morgan in front of a studio audience. Mr Brown also spoke of his three-year-old son Fraser’s battle with cystic fibrosis.

As he steps up his own pre-election campaigning, Mr Brown will today put an offer of one-to-one nursing care at home for cancer patients within five years at the centre of the party’s manifesto on health. In a speech to the King’s Fund, the Prime Minister will also make the party’s controversial plans to offer free care for the elderly a key feature of its campaign on the health service.

Andrew Lansley, the Shadow Health Secretary, said: “We support the principle of giving every cancer patient their own nurse. But I am surprised that Labour are able to find money to fund this new pledge when they are planning to cut the NHS budget.”

Alan Johnson, the Home Secretary, tried to blunt Conservative attacks over immigration, with new curbs on Britain’s student visa system yesterday. Announcing the outcome of a review set up in the wake of an investigation by this newspaper into bogus colleges, Mr Johnson increased the English language requirement for applicants and restricted those allowed to bring dependants.

As the pre-election skirmishing intensifies, Mr Cameron braced Tory candidates in target seats for a bruising fight. One witness said a tone of grim determination was set at the start of a gathering in Milton Keynes when candidates broke into nervous laughter on being told: “Please take your seats”.

The arrival of Mr Cameron and Mr Osborne, the election co-ordinator, in the party’s HQ in London’s Millbank follows an uncomfortable week for the party in which it received an official rebuke over its claims on violent crime.