The SNP has called for clarity from the UK Government on the future of two planned aircraft carriers amid fears the building programme could be scrapped.
Doubts were raised over whether the coalition will press ahead with a £5billion plan for the Royal Navy warships after BAE systems chief executive Sir Ian King told the Commons the company had been asked to consider "a number of options".
Sir Ian told MPs on Wednesday that his company had been asked to look at a number of options ranging from "one carrier to no carrier". He also warned that the situation was at a "critical point" where, if cuts were made on programmes, skilled jobs would be affected.
More than £1bn is already believed to have been invested in HMS Queen Elizabeth and HMS Prince of Wales, which are due to launch in 2016 and 2018 respectively. There are fears that any downgrading of the programme could cost thousand of jobs at shipyards on the Clyde and at Rosyth.
Glasgow Govan MSP Nicola Sturgeon said: "It is time the Tories gave us some clarity over the future of the carriers with a firm commitment to see these projects through.
"There are thousands of jobs at the best shipbuilders in the world currently reliant on this contract and the Ministry of Defence refusal to fully commit is causing great concern.
"Any sensible assessment by the Tories would show that these vessels are needed and the Clyde is the best place to build them.
"I will be writing again to the MoD and in contact with BAE to see what more can be done to make the case and secure these valuable jobs."
Jim Moohan, chairman of the Shipbuilding and Engineering Unions in Scotland and a senior organiser with GMB Scotland, said: "Speculation is creating uncertainty and concern.
"The Government have to dismiss the speculation or come forward and confirm what the situation is on the carrier project.
"A lot of money has been invested on this. The Government has a moral responsibility to end this speculation. It's one of the few green
shoots of recovery we have in the UK.
"The sad thing is there must be some substance there but we don't now what the substance is."
A defence spending review is under way, with the Ministry of Defence under pressure to cut its £36.9bn annual budget by up to 20%. Defence Secretary Dr Liam Fox is expected to make an announcement at the end of October.
A Ministry of Defence spokesman said that no final decisions have been made on the carriers.
"The Defence Secretary has made clear that tough decisions will need to be made but the complex process of a strategic defence and security review will be concluded in the autumn and speculation at this stage about its outcome is entirely unfounded," he added.
