The Ministry of Defence has banned Philip Hammond from using RAF aircraft as a row between the Chancellor and Defence Secretary Gavin Williamson escalates.

The MoD has insisted the Treasury must settle an outstanding bill for Mr Hammond’s use of aircraft attached to No32 (The Royal) Squadron before he can be allowed to fly in them again.

Mr Hammond uses A109 helicopters and BAe 146 jets from the squadron on official business, but officials who take VIP bookings for the aircraft have been told not to accept any more requests from the Chancellor until the bill is paid, according to The Times.

Mr Williamson is preparing to fight the Chancellor over potential cuts to personnel numbers after Mr Hammond was reported to have said the Army could manage with just 50,000 soldiers, a cut in numbers of around 28,000.

Any such cut would lead to resignations in the MoD, with junior minister Tobias Ellwood already on record as saying he would quit if numbers went below 70,000.