A SENIOR Conservative has suggested Lord Frost was “acting as a bit of an outrider” for a potential leadership challenger to Boris Johnson due to the reasons he gave for his resignation.

It is the first suggestion a possible leadership challenge may be mounted in the near future against Johnson after insiders believe last week’s events - including the loss of the once-safe Tory seat of North Shropshire in a by-election - have left the Prime Minister “fatally wounded”.

Simon Hoare said he took Frost’s letter citing “the current direction of travel” of the Government, fears over “coercive” Covid measures and the wish for the UK to become a “lightly regulated, low-tax” economy, as the reasons for his departure at face value.

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But the MP for North Dorset and chair of the Northern Ireland Affairs Committee told BBC Radio 4’s The World This Weekend that the issues were the same that had been raised by “at least one potential leadership candidate”.

And he said: “And I do just wonder whether he’s acting as a bit of an outrider for them, I’m just not sure.”

Hoare said while Frost’s resignation was a blow for Johnson, it was “not a hammer blow and certainly not a body blow”.

Frost will leave his post immediately. He is understood to have handed his resignation to the prime minister earlier this month, but was persuaded to stay on until January.

The Brexit minister formally tendered his resignation in a letter expressing concerns about the government’s “direction of travel.”

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Lord Frost wrote: “You know my concerns about the current direction of travel. I hope we will move as fast as possible to where we need to get to: a lightly regulated, low-tax, entrepreneurial economy, at the cutting edge of modern science and economic change.

“Three hundred years of history show that countries which take that route grow and prosper, and I am confident we will too.”

He also expressed his concerns about the Covid-19 crisis after more than 100 Tories MPs rebelled against the government to protest against the introduction of “plan B” measures.

“We also need to learn to live with Covid and I know that is your instinct too,” he wrote.

“You took a brave decision in July, against considerable opposition, to open up the country again. Sadly, it did not prove to be irreversible, as I wished, and believe you did too. I hope we can get back on track soon and not be tempted by the kind of coercive measures we have seen elsewhere.”

Johnson last night praised Frost for helping to “maximise the economic and political opportunities for Brexit.” 

The Prime Minister added in a letter to Frost: “You have helped highlight and sought to address the destabilising impact of the current operation of the Northern Ireland protocol is having on communities in Northern Ireland, which is undermining the Belfast (Good Friday) Agreement.”

After Frost’s resignation Nadine Dorries, the culture secretary, was removed from a Conservative WhatsApp group after defending the Prime Minister.

Frost’s departure came at the end of a terrible week for Johnson. There was a damaging backbench rebellion over pandemic regulations, the by-election defeat, more revelations about lockdown-breaking parties in Downing Street, and a fresh Covid crisis.

Frost dropped a heavy hint of his dissatisfaction with Johnson’s policies in a speech last month.

In it, he expressed concern the government was not taking advantage of the 'freedom' given by Brexit to chart a new political course, cutting taxes and reducing regulation.

“We can’t carry on as we were before,” he said. “And if after Brexit all we do is import the European social model, we will not succeed.”

Before the news of his departure broke, in The Mail on Sunday, it was already understood that Iain Duncan Smith was being lined up for a prominent job to placate the increasingly restive right-wing of the Conservative Party.