The Defence Secretary, Philip Hammond, has sparked a new outbreak of coalition feuding, calling for fresh welfare cuts in order to protect spending on the armed forces.
The Tory heavyweight used an interview during a trip to the Royal Marines Arctic training camp in Norway to point out that a cut of just 0.5 per cent in the welfare bill would be enough to provide the funding the military needs.
The suggestion was an early shot in the Whitehall war over the spending review, which is scheduled to take place in the next few months. But it also sparked a fresh outbreak of arguments between the Tories and Liberal Democrats over the coalition's priorities.
Tory MPs welcomed Mr Hammond's declaration he would resist further cuts to the defence budget. But there was anger among Liberal Democrats, who are set on preventing a renewed squeeze on benefits.
Mark Pritchard, a backbencher, said Mr Hammond could expect support from fellow Tories. "Defence cuts have gone far enough," he said. "There will be zero political support from Conservative backbenchers for any additional cuts." However, the Lib Dem MP Julian Huppert said building a fairer society meant helping those struggling on low incomes. "In times of austerity, it is important for us to be far more efficient in terms of Ministry of Defence spending, rather than to take money from people who really don't have spare money," he told BBC News.
Mr Hammond told journalists: "There is a body of opinion within Cabinet that believes we have to look at the welfare budget again. We're creating jobs in the private sector and should expect to see the welfare budget shrinking, not growing."
Downing Street has made it clear that defence will not be immune from cuts in the review of spending for 2015-16.