Boris Johnson’s chief strategist Dominic Cummings should not have been allowed to take up his Downing Street post after being found in contempt of parliament, a leading Conservative MP and Johnson supporter has suggested.

Cummings, who is shaping the government’s Brexit strategy in his role as the prime minister’s special adviser, repeatedly declined to appear in front of the House of Commons digital, culture, media and sport select committee select committee, chaired by Damian Collins. The committee’s long-running investigation into data misuse on social media platforms helped expose the Cambridge Analytica scandal.

Collins and his fellow MPs wanted to make Cummings answer questions about the Vote Leave campaign’s use of online political advertising during the 2016 EU referendum. Collins was instead rebuffed by Cummings who told him to “get lost”, and instead offered to set his own terms of engagement.

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As a result Cummings earlier this year became one of the few people in recent history to be found in contempt of parliament.

Asked whether Cummings should have been allowed to take up the job, Collins told an audience at the Edinburgh international television festival: “I think we have a very inadequate situation where there’s not enough real-world sanctions for those found in contempt of the house. There should be some sanction for those found in contempt of parliament, including whether they should be considered fit to hold public office.”

Contempt of parliament historically resulted in potential imprisonment but Cummings’s case showed it is now a largely toothless symbolic punishment that does little more than attempt to shame an individual into changing their ways. Facebook chief executive Mark Zuckerberg has also been threatened with a similar punishment for refusing to appear in front of the committee.

Cummings seemed nonplussed by the contempt finding, which did not affect his return to frontline politics. He is now leading policy in a government featuring politicians who have floated the idea of suspending parliament to ensure Brexit goes ahead at the end of October.

Collins, the MP for Folkestone and Hythe and remain campaigner, became an unexpectedly vocal supporter of Johnson during the Tory leadership contest, leading to speculation in Westminster that he was hoping for a ministerial job in the new government.

However, it later emerged that Cummings had been working behind the scenes to plan a Johnson government. He went on to become a major figure in Johnson’s Downing Street operation, seemingly killing any hope of Collins’s ministerial advancement.