Britain will never again have a Scottish prime minister, SNP MP Pete Wishart has told the House of Commons.
Wishart, the chair of parliament's Scottish Affairs Committee, said on Thursday this was down to devolution coupled with proposals that effectively hand MPs representing English constituencies a veto over laws which only effect England.
"I don't think there will be another Scottish prime minister," he told MPs. "I can't see the case and circumstances when that will be possible."
The UK has had several prime ministers that represented Scottish or Welsh constituencies, including Gordon Brown, William Gladstone and David Lloyd George.
Wishart also said he did not think it would ever again be possible for an MP representing a Scottish, Welsh or Northern Irish seat to become secretary of state for health or education.
The Perth and North Perthshire was speaking during a Commons debate on the government's plans for English votes for English laws (EVEL).
"It would be absurd for a Scottish MP to be secretary of state for health and education when he would be debarred form full voting entitlements," Wishart said.
The government's plans would see the introduction of a new parliamentary stage for laws that do not affect other parts of the UK.
English or English and Welsh MPs would scrutinise such legislation alone and then accept or veto it. All MPs would then continue to debate and vote on the legislation at second reading, third reading and report stage.
The SNP is strongly opposed to the plans which it says will make them second class citizens in parliament. "The mood is darkening," Wishart warned. "We are suppose to be a partner of equals in the United Kingdom."
Conservative Commons Leader Chris Grayling defended the plans. "Our plans provide a fair balance by giving England more control over decisions which it alone is affected by, while ensuring that Westminster continues to be a place where those from across the UK govern in the best interests of those living within the Union," he said.