The former head of the Royal Navy has said he would ignore instructions from the defence secretary and set up a secret unit to deal with Scottish independence were he still in post.
Giving evidence to the Lords economic affairs committee on Tuesday, Lord West of Spithead said Philip Hammond was guilty of a "dereliction of duty" by refusing to plan for the break-up if the United Kingdom.
"There are huge implications for the United Kingdom and I know jolly well that were I the First Sea Lord today, I would turn a Nelsonic blind eye to such instructions from the secretary of state for defence and I would set up a 'black team' to work out all of the options and possibilities, for example, for our nuclear deterrent," Lord West said.
"These are issues that are much too important, I believe, to suddenly do on the back of a cigarette packet."
Lord West, who appointed the Navy's top officer in 2002 went on to serve as the security minister in Gordon Brown's government.
He told peers that Scottish independence would likely mean the loss of over 10,000 jobs in Scotland as bases would shut and defence firms would move south.
"I believe that the damage to our islands' defence and the economic costs, particularly to Scotland, of separation have not been properly exposed and indeed that there have been attempts to hide the detail from the Scottish people," he said.
"I have spoken to a number of defence firms that have parts of their organisations in Scotland and they would also close in Scotland and move south.
He added: "I asked why haven't they come out and said this publicly, and they refer to a climate of fear in Scotland and that they can't say anything, which I found quite remarkable."
An MOD spokesman said: “The UK government’s position is clear: Scotland benefits from being part of the UK and the UK benefits from having Scotland within the UK.
"We are confident that the people of Scotland will choose to remain part of the UK and we are not planning for any other outcome. It is for those advocating independence to explain the nature and implications of an independent Scotland; it is the policy of the UK government to maintain the integrity of the UK.”