Plans to hand 10-year prison sentences to travellers who try to evade coronavirus quarantine rules have been criticised by legal experts and a senior Tory who branded them “utterly ridiculous”.

Sir Charles Walker said Health Secretary Matt Hancock had announced a plan that “demeans his office” and told Boris Johnson to rein in Cabinet ministers “very, very quickly”.

The influential vice chairman of the 1922 Committee of Conservative MPs also accused ministers of “robbing people of hope” after Transport Secretary Grant Shapps said it was “too soon” for Britons to book a domestic holiday.

Sir Jonathan Jones, the former head of the Government Legal Department, suggested no court would ever sentence someone to 10 years for lying on passenger locator forms.

People caught misreporting their movements could be fined £10,000 or jailed for 10 years under existing anti-forgery legislation amid moves to protect against new coronavirus strains emerging overseas, Downing Street said.

Mr Hancock announced that people returning to England from 33 “red list” destinations would have to pay £1,750 to quarantine for 10 days in Government-designated hotels.

Sir Charles told Sky News: “Utterly ridiculous thing for the Secretary of State of Health to say. Are we really going to lock people up for 10 years for being dishonest about the fact that they’ve been to Portugal?

“What a stupid thing to say, I mean a really stupid thing to say. That demeans his office and his position around the Cabinet table.”

The backbench MP also accused Mr Shapps of a “totally irresponsible” statement on holidays after the Transport Secretary suggested foreign trips will remain banned until “everybody” has had a coronavirus vaccine.

“What the Government is doing now is bordering on the very dangerous, to be perfectly honest. It is robbing people of hope, it is robbing people of something to look forward to, and it is very, very stupid and very, very short-sighted,” Sir Charles added.

“I don’t hold the Prime Minister responsible for this but I do hold his secretaries of state responsible for this and he needs to rein them in very, very quickly.”

Legal critics said the penalties are disproportionate to the offence, with former Supreme Court justice Lord Sumption arguing the penalties are more severe than those for some violent or sexual offences.

Sir Jonathan, who resigned as the permanent secretary of the Government Legal Department in September, tweeted: “If anyone is EVER sentenced to 10 years for lying on the form, I will eat a face mask. (A clean one, I’m not mad.)”

Former Conservative attorney general Dominic Grieve said 10-year jail terms were a “mistake” which would never be used by the courts.

“The reality is that nobody would get such a sentence anyway, the courts are simply not going to impose it,” he told BBC Radio 4’s Today programme.

However, Mr Shapps said the public would expect strong action if lives were put at risk by people bringing dangerous new variants into the country.

“I do think it is serious if people put others in danger by deliberately misleading and saying that you weren’t in Brazil or South Africa, or one of the red list countries,” he told BBC Breakfast.

“I think the British public would expect pretty strong action because we’re not talking now just about, ‘Oh there’s a lot of coronavirus in that country and you might bring some more of it back when we already have plenty of it here’.

“What we’re talking about now are the mutations, the variants, and that is a different matter, because we don’t want to be in a situation where we later on discover that there’s a problem with vaccines.”

Chief scientific adviser Sir Patrick Vallance said it is crucial to ease restrictions “cautiously” to measure the effects, adding: “The virus isn’t going to be particularly interested in dates.”

Mr Johnson defended his approach during a Downing Street press conference.

“What businesses up and down the country are going to want is a cautious and measured approach that is pragmatic and one that we don’t have to retreat from or reverse,” he said.

No 10 said there is no requirement for MPs to vote on the move to impose jail sentences on travellers who flout the rules because they would be convicted under current laws.

“We’re using existing legislation under the Forgery and Counterfeiting Act 1981 so there’s no requirement for a vote,” the Prime Minister’s official spokesman said.

The lack of a vote will spare the Government a further embarrassing rebellion on coronavirus restrictions.

The latest one came on Wednesday when 24 Tory MPs opposed regulations which increased fines for people caught at house parties and allowed police extra powers to access Test and Trace data.