HMS Queen Elizabeth and HMS Prince of Wales will be the biggest and most powerful surface warships ever made in the UK.

Their construction and assembly at shipyards in Portsmouth, Barrow-in-Furness, Govan and Rosyth will create or sustain 10,000 jobs across the UK, the Ministry of Defence said.

The 65,000-ton carriers, which will carry a crew of about 1,500 and up to 40 aircraft, will enter service in 2014 and 2016. The contracts for the project, which is worth a total of £4 billion, were signed in a ceremony on board the Navy's flagship, HMS Ark Royal, in Portsmouth.

The ships will be built by a group of companies known as the Aircraft Carrier Alliance, with much of the work carried out by BVT Surface Fleet, a newly-formed consortium of BAE Systems and VT Group.

Defence Secretary Des Browne hailed the project milestone as a "historic day for everyone in defence".

He said: "The two aircraft carriers will provide our forces with the world-class capabilities they will need over the coming decades. They will support peace-keeping and conflict prevention, as well as our strategic operational priorities. Today's contract signing seals the future for thousands of jobs, and ensures that we will have a Royal Navy fit for the 21st century."

First Sea Lord Admiral Sir Jonathon Band added: "These ships, with their embarked aircraft, will provide the UK with a potent and powerful aircraft carrier force that will deliver air power in support of the full range of future operations at sea, in the air and on land."

Alan Johnston, chief executive of BVT Surface Fleet, said: "This is an important announcement for BVT and for the UK maritime industry at large, guaranteeing work for years to come across the country. We are looking forward to delivering these very important ships to the fleet in the next decade and intend to begin construction work later this year."

The MoD said building the carriers would create or sustain 1,200 jobs in Portsmouth, more than 3,000 jobs on the Clyde, 1,600 jobs in Rosyth, 400 jobs in Barrow-in-Furness, 145 jobs in Frimley in Surrey and 250 jobs in Bristol and Crawley.