During a visit to Hartlepool on Monday (3 May), Johnson reiterated the need for caution when it came to restarting travel. "We do want to do some opening up on 17 May, but I don’t think the people of this country want to see an influx of disease from anywhere else," said the prime minister.

Pressed on people’s prospects of a summer holiday, Johnson said the government would "say more as soon as we can". "I think that there will be some openings up on the 17 May, but we have got to be cautious, we have got to be sensible, we have got to make sure we don’t see the virus coming back in."

International development secretary Liz Truss, meanwhile, took to Sky News on Tuesday morning (4 May) to encourage people to be patient when it came to booking holidays, but said she believed trips could go ahead if they were safe.

"We’re doing all we can to make sure we follow the roadmap and open up the economy and travel gradually," said Truss. "The really important thing is we don’t move too fast and jeopardise the progress we have made. People will have to wait a bit longer to be able to hear the news on what is happening on the travel front."

Truss stressed decisions would be based on data, and said government was supportive of safe travel. "We need to be cautious to make sure we are not simply importing the virus after we have successfully dealt with it in Britain," she said, adding: "If we are able to have people go on holiday, I don’t see any reason provided it is safe."

It comes after the All-Party Parliamentary Group on Coronavirus urged the government to maintain existing restrictions on overseas holidays to guard against the import of new Covid-19 variants that could cause a third wave of infection in the UK.

The group said additional financial support should be provided to the travel industry to weather a further delay in the resumption of international leisure travel, and called for the limits on international leisure travel should be reviewed on a quarterly basis.

Additionally, the group said urgent measures must be taken to reduce overcrowding at airports caused by additional Covid border checks, warning they risked becoming "breeding grounds" for Covid infection. The APPG on Coronavirus is made up of more than 60 MPs and peers.

Chair Layla Moran MP (Lib Dem) said it was "staggering" the government was even contemplating encouraging overseas holidays when airports were "already struggling to keep the virus and new variants at bay", while chair Dr Philippa Whitford MP (SNP) said the UK’s border management was more akin to a sieve than a shield.

Caroline Lucas MP (Green) added ministers were showing "shocking levels of complacency" about the risks posed by international travel. "We know from past experience that tourism hotspots risk becoming Covid hotspots, with people mixing from all over the world," said Lucas.

"Instead of giving the green light to overseas holidays, we should be providing ongoing support to the travel industry and reversing aid cuts that are undermining the global fight against Covid-19."

’Ministerial mixed messaging’

The TSSA union, which represents high street travel staff, as called on the government to "provide much-needed clarity" on international travel. “We have been waiting for months for the government to set out a proper strategic plan to support our travel trade in this pandemic and heard nothing," said general secretary Manuel Cortes.

"Ministers must now provide much needed clarity about what travel will be allowed later this month. After everything they have been through, millions of people around our country want to know whether they should be taking holidays abroad this summer – and how they can do so safely.

"So far, ministerial mixed messaging has cost far too many jobs within our travel industry. The Tories have had a tin ear when it comes to travel, with workers and businesses suffering. They now need to provide both hope and clarity.

"The only way to do that is to set out a foolproof set of instructions for the public about what will and won’t be possible as we head towards summer. That should not be too much to ask for any competent government."