The Ministry of Defence claimed yesterday that Britain's overstretched armed forces were at 96.8% of full manning levels at the end of June and that 2250 more recruits signed on in the past 12 months than in the comparable period for 2007.

It also said that fewer people of all ranks had left early in a process known as voluntary outflow than at any time since March 2006, despite the demands of a challenging operational tempo and the family strains of repeated combat tours to Afghanistan and Iraq.

But The Herald can reveal that the Army remains short of more than 4000 soldiers and the Royal Navy is struggling to crew what remains of its shrinking surface fleet and retain qualified specialist engineering staff for nuclear submarines.

While figures produced by the Defence Analytical Services Agency show that an extra 1830 newly trained soldiers, sailors and airmen have been posted to units in the past year, the three services are still collectively 5790 men and women below "bayonet strength".

The most serious gaps are in the infantry (1600 short), gunners (718), vehicle mechanics and recovery engineers (600), bomb disposal experts (49% short) and medics at every level (30% average deficit).

Most infantry battalions are 80-90 men under complement - the equivalent of one of their three rifle companies - and have to rely on borrowing soldiers from other units.

The Navy also has only half of the Harrier pilots it needs and just over 40% of the flying instructors required to train more for its new carriers, while the shortfalls for able seamen for the frigate and destroyer flotillas are also running at 40% and the strategic missile and attack submarine fleets lack one in four of their required nuclear watchkeepers and underwater sensor experts.