The Conservative Party should apologise for a quip made by Margaret Thatcher's press secretary in 1983, an SNP MP has said.

It comes after newly declassified government files showed Thatcher aide Bernard Ingham had suggested a "North Sea blow out" could help distract the public from a major protest against nuclear weapons.

The SNP's energy spokesman at Westminster, Callum McCaig, demanded Prime Minister Theresa May apologise for the remarks on behalf of her party and the UK Government.

Government figures at the time were worried CND-organised protests at the Greenham Commons airbase could have enough of an impact to prevent the deployment of US nuclear weapons in the UK.

Ingham asked if there was anything that could be done to "neutralise the television appeal of these demonstrations".

He added: "They will secure less airtime and have less impact if something more newsworthy in television terms occurs - e.g. (to be brutal) a North Sea blow out; an assassination attempt on the Pope, etc; some awful tragedy."

The files, released the National Archives at Kew, west London, show Thatcher's aides instead decided to divert the media's attention with the visit to Australia of Prince Charles and Princess Diana with baby Prince William.

McCaig, who represents Aberdeen South, said: "To speak flippantly of a 'North Sea blowout' in Scotland shows utter contempt for the lives and safety of the men and women who work offshore in the oil and gas industry every day. The disrespect shown to them, no matter how long ago, is utterly unacceptable.

"This bizarre exchange is beyond distasteful and occurred only five years before the Piper Alpha disaster, which killed 167 men.

"Most people consider offshore incidents to be something avoided at all costs, not to be joked about, and certainly not to be seen as a PR opportunity.

"Once again these comments unfortunately highlight the Conservative Party's long-held attitude toward Scotland - seen through decades of Westminster governments Scotland did not want for imposing devastating cuts and dumping a brand new generation of obscene and redundant nuclear weapons on the Clyde."

The Aberdeen South MP added: "I have written to Theresa May calling for her, as leader of the Conservatives and Prime Minister, to issue an apology on behalf of her party and the UK Government for these shameful statements."

Downing Street and the Conservative Party have both been approached for a response, with the Conservatives saying they were unlikely to comment.