Cost constraints mean that only 148 of 227 Challenger 2 tanks will be upgraded

Defence chiefs have expressed anger that Britain is to mothball a third of its tanks, leaving it with fewer than Serbia, Cambodia or Burma.

The military is planning to revamp only 148 of its 227 Challenger 2 tanks because of cost constraints, The Times has learnt. That would send the armed forces down to 56th in the global league table of number of tanks available.

The remainder of the Challenger 2s, which entered service between 1998 and 2002, are expected to be used for parts. It is possible that some could be patched up for deployment in an emergency.

The army has had £31 billion stripped from its budget since 2010, according to a senior defence insider.

At present Britain’s 227 tanks earn it a