Former First Sea Lord Admiral Lord West gave evidence on Tuesday to the defence select committee on the procurement of new ships for the Royal Navy.
And he raised concerns about the apparent lack of cash available to fund the construction of new Type 26 frigates.
The issue was raised at Prime Minister’s Questions by the SNP’s Steven Paterson.
The MP for Stirling said: “Yesterday at the defence committee the former first sea lord Admiral Lord West commented that the Ministry of Defence had effectively run out of money for shipbuilding.
“Given reports that another Russian submarine has had to be escorted out of the UK waters overnight does the Prime Minister share my concerns that the delays to work beginning at the Clyde ship yards on the new frigates is causing real problems and agree it’s essential that the money is allocated to deliver this programme in full and on schedule?”
Mr Cameron replied: “It is certainly not the case that this country in any way has run out of money or run out of ambition when it comes to shipbuilding.
“We are currently building the two largest ships the Royal Navy has ever had and we are going to shortly be commissioning the Type 26 programme as well as the off-shore patrol vessels.
“The point I would make to you is there is only one way we could threaten shipbuilding on the Clyde and that would be to pull out of the United Kingdom and see the jobs be decimated as a result.”