Plans to curb legal challenges against the government are to be fast-tracked, despite widespread criticism that Boris Johnson is plotting revenge for court defeats over Brexit.

The move will be the first act of a new “constitution, democracy and rights commission”, which ministers insist is needed to “restore trust in our institutions and in how our democracy operates”.

A former Tory MP has already warned the plans signal “a monstrous attack on the courts” – while constitutional experts alleged the motive is retribution for the setbacks inflicted by the Supreme Court on the last two prime ministers.

Until now, Downing Street has refused to explain its intentions, but a government source has now revealed that restricting judicial review will be the first target.

They said the prime minister was determined to stamp on challenges mounted by people not directly affected by decisions purely “with the aim of frustrating” the government.

“There are huge numbers of judicial reviews going through every year,” the source said.

“In some instances, they find the government doing something wrong, and that’s entirely right, but in other cases they are clearly being brought for political motives.”

Plans would be drawn up “within months”, the source said, adding: “If action can be taken in quick time that can protect taxpayers’ money, then we will do that.”

Bizarre: Boris Johnson drives 'Brexit' digger through boxes Show all 8 1 /8 Bizarre: Boris Johnson drives 'Brexit' digger through boxes Bizarre: Boris Johnson drives 'Brexit' digger through boxes Conservative party leader Boris Johnson drives a JCB through a fake wall POOL/AFP via Getty Images Bizarre: Boris Johnson drives 'Brexit' digger through boxes Prime Minister Boris Johnson during a visit to JCB cab manufacturing centre in Uttoxeter, while on the General Election campaign trail. PA Photo. Picture date: Tuesday December 10, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative party leader Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire, on December 10, 2019. - Britain will go to the polls on December 12, 2019 to vote in a pre-Christmas general election. (Photo by Ben STANSALL / POOL / AFP) (Photo by BEN STANSALL/POOL/AFP via Getty Images) BEN STANSALL AFP via Getty Bizarre: Boris Johnson drives 'Brexit' digger through boxes Prime Minister Boris Johnson sits in a cab of a JCB during a visit to its cab manufacturing centre in Uttoxeter, while on the General Election campaign trail. PA Photo. Picture date: Tuesday December 10, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative leader Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Britain, December 10, 2019. Ben Stansall/AFP/Pool via REUTERS POOL REUTERS Bizarre: Boris Johnson drives 'Brexit' digger through boxes A sign made for a visit by Prime Minister Boris Johnson to the JCB cab manufacturing centre in Uttoxeter, while on the General Election campaign trail. PA Photo. Picture date: Tuesday December 10, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative party leader Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire, on December 10, 2019. - Britain will go to the polls on December 12, 2019 to vote in a pre-Christmas general election. (Photo by Ben STANSALL / POOL / AFP) (Photo by BEN STANSALL/POOL/AFP via Getty Images) BEN STANSALL AFP via Getty Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative party leader Boris Johnson reacts as he sits in the cab of a drives a Union flag-themed JCB, after driving through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire, on December 10, 2019. - Britain will go to the polls on December 12, 2019 to vote in a pre-Christmas general election. (Photo by Ben STANSALL / POOL / AFP) (Photo by BEN STANSALL/POOL/AFP via Getty Images) BEN STANSALL AFP via Getty

The Independent revealed the mounting concern over the plans in November, after they were included in the Conservative manifesto for the general election.

Dominic Grieve, the former Conservative attorney general, said he feared “a monstrous attack on the courts and its clear role in interpreting and upholding our constitution”.

Martha Spurrier, the director of human rights organisation Liberty, said: “The executive lost a huge judicial review on prorogation. It would be a real concern to see anything which would water down people’s rights.”

And Gina Miller, the businesswoman who won the Article 50 case, highlighted a separate hint at expanding the use of the royal prerogative, asking: “Is Boris Johnson intending to become a dictator?”

She expressed fears that the government would seek to ram through plans for the future relationship with the EU without proper scrutiny by MPs.

At prime minister’s questions, Mr Johnson defended his intentions after a Tory backbencher made what appeared to be a veiled swipe at the Supreme Court’s actions.

Asked, by Desmond Swayne, to “let bygones be top priority”, Mr Johnson replied: “Our independent courts and legal system are admired around the world.