The Conservative Government and Labour “appear to be in complete denial about the contribution of Brexit to the cost-of-living crisis”, an SNP MP has warned.

A cross-party committee of MPs should be established to investigate the causes of the cost-of-living crisis and solutions to it, the SNP’s Scotland spokeswoman, Dr Philippa Whitford, told the Commons.

But the SNP’s proposal was dismissed as a “crackpot” idea and a “waste of taxpayers’ money” by Scotland Office minister John Lamont.

Opening an SNP-led debate, Dr Whitford said: “As we approach the seventh anniversary of the referendum, one of its key architects may have just left the stage (Boris Johnson) but Brexit’s disastrous legacy will impact people across the nations of the UK for years to come.

“I know as a doctor that the first step in dealing with any problem is to admit that you have one, but both this Government and the Labour Party appear to be in complete denial about the contribution of Brexit to the cost-of-living crisis.”

She added: “If he wants to reduce some of the damage of Brexit, the Labour leader should support the idea of a committee to identify proposals that could be put to the EU prior to the review of the trade and co-operation agreement in 2026. Otherwise, what is the plan? Close his eyes, click his red heels together and make a wish?”

Intervening, Liberal Democrat MP Jamie Stone (Caithness, Sutherland and Easter Ross) said the structure of the committee meant the door was “locked against” his party being members of it.”

Conservative frontbencher Mr Lamont said a debate “which starts from the unfounded position that the UK’s exit from the European Union is to blame for any and all woes is not the best use of this House’s time”.

He added: “(Russian President Vladimir Putin’s) illegal invasion of Ukraine, coupled with the economic after-shocks of Covid, have caused huge disruptions to the global economy. No country is immune to this. However, we are benefiting from the swift action taken by this United Kingdom Government to mitigate the worst of these impacts.”

He went on: “The SNP’s motion to establish a select committee to look at the cost-of-living crisis is not only unnecessary duplication of other work by this Parliament, but it is a complete waste of taxpayers’ money.

“The total anticipated cost to the House of Commons for this crackpot idea is in the region of £463,000 per annum … and, in addition, there would be extra costs to adapt Parliament’s committee rooms to accommodate this massive new committee.”

Labour’s shadow secretary of state for Scotland Ian Murray accused the SNP of a “have their cake and eat it” approach.

He added: “Their solution to Brexit, which in their words and mine and many others was a bad idea, is to have Scexit, which indeed would be many magnitudes worse than Brexit. They want to repeat the same mistakes and do the same thing.”

He went on: “While they keep blaming Brexit, and they’re right to say that Brexit has a contribution to the cost-of-living crisis, they’re letting this Government off the hook.”

On the cost-of-living committee proposal motion, he said it was “when looking at the small print that the flaws of this proposal become clear”.

He added: “Now I’m left wondering if the real reason that this is being proposed is for the SNP to try and get one of their many disgruntled members of their group an additional salary payment as being committee chair.”

Conservative David Duguid (Banff and Buchan) argued the motion was “straight from the SNP’s playbook of every problem is Brexit, every solution is independence”.

Earlier at Prime Minister’s Questions, SNP Westminster leader Stephen Flynn called on Rishi Sunak to “apologise for the cycle of misery that Westminster has caused”.

He said:  “There is an elephant in this here chamber when it comes to the dire economic circumstances facing the UK, and that’s Brexit.

“The Tory benches, they don’t want to accept it, and the Labour Party, they don’t want to talk about it, but whether it’s food prices, energy prices or indeed mortgage prices, households in Scotland are being shafted by Brexit. So can I ask the Prime Minister will he apologise for the cycle of misery that Westminster has caused?

Rishi Sunak replied: “While his party leader calls Nicola Sturgeon the most impressive politician in Europe, we are getting on delivering for the people of Scotland.”

The SNP’s motion calling for the creation of a new Cost-of-Living Committee was rejected by 43 votes to 260, majority 217.