Cameron and Clegg set to draw a line under Coalition infighting

PM warns feuding Tories and Lib Dem against a descent into 'division and navel-gazing'

David Cameron and Nick Clegg will stage a show of unity today as they attempt to turn the Government's focus back on to rebuilding the economy and to draw a line under Coalition infighting.

The Prime Minister reinforced the message yesterday and warned feuding Tories and Liberal Democrats – who leave Westminster tomorrow for their summer recess – against a descent into "division and navel-gazing".

Despite his plea, Coalition tensions were underlined by renewed calls from Liberal Democrats for Mr Cameron to deliver on Lords reform and demands from Tory MPs for him to take a tougher stance against Mr Clegg's party.

Mr Cameron will chair a Cabinet meeting outside London today as the Government details a £9bn package which it is hailing as the most widespread improvements to Britain's railways since the 19th century.

It will say that £4bn is being found on top of a previously-announced £5bn to electrify rail links between the south coast and the North of England, upgrade routes radiating out of Manchester and electrify more track in south Wales.

Individual stations will also be face-lifted and freight services improved in an effort to persuade heavy industry to switch from road to rail. Ministers will fan out around the country to highlight the message that the Government is committed to stimulating the economy – and creating jobs – through major infrastructure projects.

Mr Cameron's appeal came after a torrid week for the Coalition in which a rebellion by 91 Tory MPs forced the Government to put its Lord reform plans on hold. Angry Liberal Democrats responded by threatening to scupper Conservative plans to redraw the parliamentary map – thought to be worth 20 seats to the Tories.

Graham Brady, the chairman of the Conservative backbench 1922 Committee, said he believed the coalition was "very likely" to end before the general election, set for 2015.

"I think it would be logical and sensible for both parties to be able to present their separate vision to the public in time for the public to form a clear view before the election," he told BBC Radio 4's The Westminster Hour.

He added: "Of course, it is always possible that that moment of separation could come sooner. It's very difficult to predict when that might be."

Writing in The Sunday Times, Mr Cameron acknowledged there were "profound areas of disagreement" between the parties but said it was essential that did not stop them working together in the national interest.

"These differences matter and at the next election they will help define us. But we're not in an election, now. We're not even close," he wrote. "[People] will not tolerate division and navel-gazing. They know that the problems are big and they do not want to see politicians fall out in the process of dealing with them."

But the former Defence Secretary, Liam Fox, reflecting the feelings of many Tory backbenchers, said that his party had a "particular problem which is the Liberal Democrats". He said: "What I think they have to remember is that they are a sixth of the Coalition, not half the Coalition."

Meanwhile the Liberal Democrat Energy Secretary, Ed Davey, called on Mr Cameron to ensure his backing for the Lords reform plans. "The Coalition Agreement isn't a pick-and-mix agreement, you've got to deliver on all of it. We're expecting the Prime Minister and the Conservative Party to deliver on the Coalition Agreement."

And the former Liberal Democrat leader, Sir Menzies Campbell, warned that the party's MPs might "find it very hard to swallow" the proposed boundary changes unless Lords reform goes ahead.