The UK Supreme Court this week heard arguments over a prospective independence referendum Bill, after being asked to consider if its passage would be in the powers of the Scottish Parliament.
If the court finds Holyrood can legislate for another vote, Nicola Sturgeon has said she wants to hold another vote in October next year.
During an event hosted by the Institute for Government (IfG) on Thursday, host Akash Paun asked if the UK Government could simply legislate against Scotland holding a referendum.
"Only if they were completely insane - which they might be," responded Professor Adam Tomkins, who stood down from Holyrood last year.
"I think that would be a tactic or a strategy which would succeed only in accelerating Scotland's divorce from the rest of the United Kingdom."
Prof Tomkins, who has been a vocal critic of the Prime Minister's performance since she took office, added: "I wouldn't put it past Truss and her advisers to think that was a good idea, because I think Truss and her advisers are very badly mistaken about what unionist strategy should be."
The former Scottish Tory frontbencher went on to say he was "just about still in the Conservative Party".
Prof Tomkins warned the union had become the dividing line for most Scots, more so than individual parties or Brexit, adding: "The problem with that is all sorts of other things which needed to happen in Scotland are not happening because the tribally divided nature of our politics is somehow preventing them from happening.
"I want my kids to grow up in a Scotland that is more prosperous, with better schools, with better infrastructure, but Scottish prosperity is being held back - whatever you think of growth and Trussinomics and all the rest of it - because of our constitutional obsession."
The constitutional law professor pointed to issues in education, infrastructure and the drug deaths crisis as issues the country struggled to deal with because of "tribal constitutional politics".