The trade was still awaiting details of stricter restrictions set to be applied at UK borders, after the prime minister continued to give little clarity in response to questioning on Wednesday.

Labour leader Keir Starmer, and other MPs, pressed Boris Johnson on the issue at Prime Minister’s Questions in the House of Commons but he were given scant information in response.

When Starmer asked “why are these measures not introduced already?” and pointed out “they have been briefed to the media for days”, Johnson replied: “It’s vital that we protect our borders and protect the country from readmission of the virus from overseas. We will continue to take whatever action is necessary to protect the country from the readmission of the virus.”

Asked again by the Scottish National Party’s Ian Blackford, Johnson said: “We will make sure to protect our borders from the readmission of the virus” and “bring forward further measures”.

Those questions followed a similar response to journalists at the Downing Street briefing on Tuesday night, after Cabinet Office minister Michael Gove told the BBC tougher restrictions would be introduced at the UK borders.

Agents had said that it was “frustrating” that a “vague comment” from the prime minister was all businesses had to work with to advise their customers.

Clive Wratten, chief executive of the Business Travel Association (BTA), said: “As we enter the first full day of our third national lockdown, the BTA supports the government in prioritising public health. However, trailing an announcement on the introduction of testing for travellers arriving in the UK and further international travel restrictions, that then doesn’t happen, is causing wholly avoidable stress and uncertainty at a time when our industry is already fighting for survival.

“The travel management community urgently needs clarity on when testing will be introduced, and reassurance that our industry will not be thrown off the cliff by a hard stop to furlough at the end of April.”

He added: “We urge the Government to work with us and other badly impacted sectors to craft targeted support packages to avoid further mass job losses and to enable vital industries like ours to contribute to the British economy once more.”

In the Commons, Johnson was also asked to provide sector-specific support to the aviation and aerospace industry by the DUP’s Jim Shannon. Johnson said he was “quite right” that aviation was a “vital industry for our country”, adding: “We will be ensuring we will be doing everything we can to get the aerospace industry in the UK back on its feet as quickly as possible.”