The Ministry of Defence will have its budget increased by nearly £8bn over the next three years.
In a statement to the Commons, defence secretary Des Browne told MPs that the added investment was part of announcements ahead of the government's full spending review in the autumn.
Browne said that during the CSR period the armed forces would get £7.7bn, an average annual real terms increase of 1.5 per cent.
"It is evidence of the government's commitment to defence and to the men and women who serve with the utmost bravery in our armed forces," the defence secretary said.
A considerable part of the extra cash will be spent on two long-awaited new aircraft carriers.
Browne said orders were being placed for the two 65,000 tonne vessels - and that they would be built in shipyards on the Clyde in Scotland.
"The carriers represent a step change in our capability, enabling us to deliver increased strategic effect and influence around the world at a time and place of our choosing," he said.
The ships are due to enter service in 2014 and 2016 at an estimated cost of £3.9bn.
The programme is expected to create or safeguard 10,000 jobs around the UK, with more than 1,000 people employed on the actual construction at shipyards at Govan, Barrow, Rosyth and Portsmouth.