I realise all that, Sallying. And I almost agree with this:
"If Scotland leaves the UK there is no incentive for the navy to build ships there and every incentive to build them in Portsmouth."
But my question was about why there's been a tendency to claim that any defence contract not placed within the UK has to be put out to tender, when that's not actually true.
RE Portsmouth/Glasgow. That was a decision that BAE systems took, and political considerations aside (I hope you aren't suggesting that it was a bribe to vote no!) BAE chose the Clyde because it was more cost effective, and there are additional capacities there which don't exist in Portsmouth. Given that BAE is a British company, and is the MOD's contractor of choice, and will still be a British company postreferendum, I'd say that there is still some incentive for BAE, if given the contract, to built them on the Clyde. A lot of people would have you believe that this would be impossible due to EU legislation, but that's not at all the case.