Britain’s biggest holiday company has demanded clarity about where it will be permitted to take travellers this summer.

At the weekend, Tui confirmed it would restart operations from the UK on 11 July – even though the Foreign Office still warns against all but essential travel anywhere abroad.

Andrew Flintham, managing director of Tui UK and Ireland, told the BBC’s Today programme: “We did that without any real official confirmation from the government.

“We were hoping that was the direction they were going.”

The government currently has a “double lock” in place designed to prevent overseas tourism. The Foreign Office warning, if ignored, voids travel insurance.

In addition, the new blanket quarantine law requires all returning holidaymakers to self-isolate for two weeks.

On Monday the transport secretary, Grant Shapps, said both restrictions will be eased. It is expected they will be lifted for some countries from next Monday, 6 July.

Mr Shapps said: “I will announce further details including a full list of the countries and territories from which arriving passengers will be exempted from self-isolation requirements later this week.

“Separately, the Foreign and Commonwealth Office is reviewing its travel advice. Further details will be announced later this week.”

But Mr Flintham said: “We take five million people on holiday every year. We can’t start up our operations on a Tuesday when we are told we can go from a Wednesday – which is why we took the decision to almost go ahead.

“We really do need that certainty. If the government can give us that list of destinations we can go to, we can make sure our customers will be ready to enjoy a holiday there.

“We’ve been frustrated by how long it’s taken.

“We clearly need to restart life, we need to restart our business.”

Much of the EU opens up to European visitors from 1 July, but on Monday the Greek prime minister said that flights from the UK would not be allowed until 15 July.

But the Tui boss welcomed the announcement from Athens, saying: “Greece coming out, saying we expect our customers to be able to go there from 15 July is a good thing. We can plan firmly and make sure people can enjoy their holidays there.

“The conversation with overseas countries, as Greece has demonstrated, is a two-way conversation.

“There are still going to be a few bumps in the road, and I still think they’ll be some countries that won’t open up, which means we will be cancelling a few more holidays – but hopefully not as many as we’ve been cancelling.”

Mr Shapps said: “Throughout this process public safety has been at the heart of our decision making.

“We have been guided by the science and worked closely with health and policy experts from across government to ensure the steps we are taking are gradual and will minimise the risk of new Covid-19 cases while helping to open our travel and tourism sector.”