Scottish shipbuilders have welcomed the news that they will be part of a £4bn deal to build two aircraft carriers.
HMS Queen Elizabeth and HMS Prince of Wales will be built by a consortium to be formed between BAE Systems and its rival, VT Group.
Much of the work will be carried out at BAE's Govan shipyard in Glasgow and by Babcock Marine in Rosyth, Fife.
It is hoped the Ministry of Defence announcement will lead to the creation of 10,000 jobs across the UK.
The rest of the work will be carried out in Barrow-in-Furness and Portsmouth.
The MoD has not yet signed the contract but the plans are due to be put to parliament.
The project was first announced in 2003, but was delayed due to MoD spending plans.
The 65,000-tonne carriers are due to enter service in 2014 and 2016 with each likely to carry 36 fighter jets as well as four early warning aircraft.
Mike Turner, BAE Systems chief executive, said: "This is an important milestone in the development of the CVF (Future Aircraft Carrier programme) and plays a major part in the long term sustainability of the UK naval sector and the transformation of our business.
"The programme will provide a strong order book and forward workload over the coming years and, most importantly will provide our armed forces with significantly enhanced capability."
Sean Donaldson, CVF project director at Babcock Marine, said: "Today's announcement is fantastic news for Scotland and for Fife in particular.
"This contract will secure and grow our engineering skills base, enable us to increase the number of apprenticeships we offer and to employ local contractors wherever possible.
"Babcock Marine is proud to have a major role in the production of these vessels.".
The announcement was welcomed by Scotland's Deputy First Minister, Nicola Sturgeon, the Nationalist MSP for Glasgow Govan.
She said: "This will be welcome news for all those working at Govan, Scotstoun and Rosyth.
"The ongoing uncertainty caused by the Ministry of Defence's delay was, according to BAE's own figures, threatening jobs on the Clyde.
"Scottish shipyards are the finest in Europe and today's announcement ensures a strong future for shipbuilding on the Clyde."
Defence Secretary Des Browne, who is also Secretary of State for Scotland, said: "The two aircraft carriers will provide our frontline forces with the modern, 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.
"This is an important day for the project and I am delighted that we are moving closer to signing the contracts for the manufacture of the carriers."
Willie Rennie, the Liberal Democrat's defence spokesman and MP for Dunfermline and West Fife, said: "It has taken a very long time to take this small step.
"It is frustrating that the main contracts have still not been signed but at least we are edging towards a conclusion to this marathon of a process.
"The pressure on the government seems to be paying off. However, they must never again be tempted to let the timetable slip.
"This is a massive opportunity for Scotland and our economy and I am determined to make sure the effects are felt for many years to come."