Clegg and Cameron
David Cameron and Nick Clegg continue to move in different directionsReuters

David Cameron is embarking on an "economic tour" of England amid yet more eruptions in the increasingly stormy relationship between the coalition government allies as they seek to distance themselves from each other.

This time, the rows are over the much-criticised bedroom tax and controversial onshore windfarms. Both are big issues that have caused political problems for the Liberal Democrats and the Tories respectively.

And just to add further fuel to the fire, Cameron is to use his four-day tour to declare that raising the tax threshold to £10,000 is "one of the proudest things I have done in government".

Those 10 little words, most particularly the "I", have infuriated the Liberal Democrats who point out that it was their policy, not Cameron's, and claim he is blatantly stealing the credit.

Meanwhile, in a dramatic about-face, the Liberal Democrat president Tim Farron has withdrawn his party's support for the government's bedroom tax claiming it has caused huge social problems.

His remarks reflect the findings of the work and pensions committee of MPs who said the reforms were causing severe financial hardship and distress to vulnerable groups, including disabled people.

Farron's move is a clear attempt to distance his party from any electoral consequences of the policy, and is part of the ongoing "differentiation" strategy being pursued by both coalition parties.

But it will also be seen as part of Farron's personal differentiation from Clegg platform should there be a leadership election after the general election.

Labour has described the move as "breathtaking hypocrisy" because the Liberal Democrats voted for the policy and helped push it through parliament.

Meanwhile, Cameron is considering including a pledge in the Tory manifesto curbing the growth in onshore windfarms which have sparked protests in some traditionally Tory shires.

Just a day after the Lib-Dems suggested Clegg had stopped such a move, senior Tories were briefing that Cameron agreed with the critics.

Clegg said: "The Tories were, before the last election, committed to the environment. They seem to have gone off that now."

But it is the prime minister's determination to claim the increase in the tax threshold, and his boast that he has taken three million people out of tax altogether, that has most incensed the Lib-Dems.

Clegg is painfully aware of the danger that the Tories will take the credit for all the positive, popular policies the government has introduced since 2010 while he will take the rap for the unpopular policies. And he still has not recovered from his tuition fees U-turn after the last election.

Cameron is determined to keep up the political momentum the Tories have gained since George Osborne's agenda-setting budget with his tour of the regions of England. Scotland is, perhaps unsurprisingly, not on the agenda.

This is all just further evidence that election campaigning is in full swing as all the parties look towards next month's Euro poll as a vital staging post towards the general election in 2105.

It is going to get much worse in the coming 12 months.