Defence Secretary Des Browne 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 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. This is an historic day for everyone in defence.'

Baroness Taylor, the minister for Defence Equipment and Support, said: 'This is truly a national project, involving companies from the Clyde to the Solent. Construction work will create or sustain around 10,000 UK jobs at the peak of production.

'I am delighted that we have signed the contracts for manufacture today and I look forward to first cutting of steel for this exciting project later this year.'

First Sea Lord, Admiral Sir Jonathon Band, said: 'I am delighted the contract for the two new aircraft carriers, to be named HMS Queen Elizabeth and HMS Prince of Wales, has been agreed and signed.

'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.'