David Cameron stressed his commitment to the coalition as ministers prepared to debate face-to-face across the Cabinet table today, amid significantly heightened tensions between the Westminster government partners.

It is the first meeting since last Thursday’s (5 May) heavy poll defeats for the Liberal Democrats, who suffered severe losses in local elections and saw voting reform decisively rejected by the public.

But party leaders insisted at the weekend that the results would not prevent the power-sharing administration getting on with the business of running the country.

The prime minister told the Sun newspaper: “We are committed to a coalition government because it is the right thing to do. I said I wanted it to last for five years and I meant it.”

Insisting the coalition government had “chalked up a lot of achievements”, he added: “The challenge for the next period is going to be how do you have two parties perhaps wanting to make their voices heard more clearly, but still achieve that coherence?

“I think the Lib Dem top team and the Conservative top team will still work together very well. But that is going to be the challenge.”

Speaking ahead of tomorrow’s anniversary of his first 12 months as prime minister, Mr Cameron said it was “inevitable” that there would be “more public airing of differences”.

Deputy prime minister Nick Clegg has already signalled his intent to demonstrate more Lib Dem muscle - with Tory-led NHS reforms the battleground yesterday for heated exchanges in the Commons.

Mr Clegg has threatened to veto the reforms unless they are substantially improved as part of attempts to reassert his party’s independence after last week’s bruising.

Despite accepting the need for “substantive” changes however, a defiant Mr Lansley yesterday refused to abandon the “principles” of the reforms.