The Royal Navy has 33 admirals earning an average of more than £120,000 a head to manage its 75-strong surface fleet, according to figures revealed in a parliamentary written answer.

The Senior Service's £4m top brass includes two sea lords, six vice-admirals, and 25 rear-admirals to command 35,000 sailors, 25 destroyers and frigates, two ageing aircraft carriers, a helicopter carrier, two assault ships, and a collection of mine-warfare, offshore patrol, fishery protection, resupply and survey craft.

There are also 13 submarines, including the four Trident missile boats, and nine hunter-killers in the smallest Navy since Nelson's day. The total manpower of the Royal Navy includes 290 captains - the equivalent of 11 for every destroyer or frigate - 1090 commanders, and 2320 lieutenant-commanders among the 7480 officers in its ranks.

The MoD last year imposed a promotion freeze on everyone above the rank of lieutenant-commander, which equals majors in the Army and squadron leaders in the RAF, to save money and help clear the top-heavy log-jam through natural wastage.

It says 15 of the rear-admirals on the active list are in operational RN or Nato posts, with others serving in tri-service commands. A naval source added yesterday that it was unfair to equate the number of senior officers with the number of warship hulls in service, since many of the individuals were "performing essential roles in shore command, training, logistics and joint headquarters".

Meanwhile, steel giant Corus has beaten off international competition to win a contract to supply 80,000 tonnes of steel to the Royal Navy for its two new aircraft carriers. Most of the steel will be manufactured at the firm's sites in Dalzell, near Motherwell, Scunthorpe, North Lincolnshire and Skinningrove in Teesside.

The £3.8bn carriers, HMS Queen Elizabeth and HMS Prince of Wales, are due to enter service in 2014 and 2016 respectively.