Ousted defence minister Nick Harvey challenged David Cameron today over the "severe cost" of replacing Britain's Trident nuclear missiles.
During Prime Minister's questions, the North Devon MP demanded to know what the government would do when a series of huge military bills come due at the same time.
It's a thorny issue for the Prime Minister, who keeps claiming that Britain is broke.
Mr Harvey said that the coalition needs to find the cash for the Joint Strike Fighter, new frigates, army vehicles and killer drones while also coughing up for new nukes.
Without offering any details, Mr Cameron claimed that everything was fine as the government had "sorted out the defence budget."
Lib Dem Mr Harvey was tossed out of the Cabinet in September's reshuffle.
Fire Minister Brandon Lewis probably had a fair idea what Sir Ken Knight would deliver when he asked him to conduct an "independent" report into fire and rescue services in England.