People seeking to leave Britain from Monday will have to show a new permit proving they are travelling for essential reasons in a move to stop Easter holidays.
The crackdown – enforced by on-the-spot fines and the threat of criminal action – came as holiday destinations including Cyprus, Seychelles, Greece and the Spanish islands rushed to open to vaccinated Britons.
There is concern in Whitehall over increasing levels of rule-breaking, particularly among the 40 per cent of the adult population who have now been vaccinated, amid growing questions about the need to continue abiding by lockdown restrictions. Holidays in the UK or abroad are currently illegal.
Ministers have banned Easter holidays in the UK, with most family gatherings also outlawed until mid-April. The new permits appear designed to stop those considering foreign getaways until at least the middle of May.
The crackdown on holidays and other liberties comes despite increasing evidence that Covid is in retreat, as Matt Hancock, the Health Secretary, announced that infection rates, hospital admissions and deaths had seen some of their biggest falls since the start of the pandemic.
The travel permit move prompted a backlash from Tory MPs and travel bosses, who described it as "bizarre", "barmy" and "ridiculous", as it emerged two in five of all UK adults have now been vaccinated.
It also comes despite fresh moves from the government seemingly designed to boost confidence in returning to the office.
The Department of Health announces on Saturday that workplace testing will now be available to all businesses, including those with fewer than 50 employees.
Businesses can register for and order the lateral flow tests from Saturday. So far more than 3,500 have signed up to offer workplace testing programmes, and more than 14,000 have registered their interest in offering rapid testing.
Sir Graham Brady, the chairman of the Tory backbench 1922 Committee, said: "With the progress of the vaccine programme and the real fall of positive tests for Covid in the UK, it's time that we were starting to get rid of intrusive regulations, not bringing in new ones.
"This threatens to be yet another bureaucratic nightmare which will limit people's freedom, give too much control to the state and will achieve nothing whatsoever in the control of Covid."
Henry Smith, the chairman of the all-party Future of Aviation Group, said: "I genuinely don't get it. It's bizarre – it's barmy. It's a further massive disincentive for anyone to get on an aircraft. We have got passenger locator forms, and quarantine for 'red list' countries. If you need an ID document, you are going to have a passport. There are civil liberty implications."
The move was also condemned by the travel industry. Paul Charles, the co-founder of Save our Summer, said: "It adds a further layer of complexity to travel when the data is showing things are getting better. The Government needs to say when it will remove it and open up the UK for business."
Forms requiring people to spell out their reasons for travelling were signalled six weeks ago by Priti Patel, the Home Secretary, but were only unveiled on Friday for their launch on Monday.
The Department for Transport (DfT) warned that anyone turning up at an airport without their form and supporting documentation to justify their journey faced £200 fines and would be barred from their flights.
The DfT said police were stepping up patrols at ports and airports and would be conducting spot checks on passengers requiring them to show the new forms. Anyone found to be flouting the ban on non-essential travel faces fines starting at £200 but escalating to £6,400.
The three-page "travel declaration form" asks people to set out their reason for having to go abroad during the travel ban and to bring "evidence" such as an employer's letter and professional ID card if their justification is work.
It came as Mr Hancock revealed that Covid cases had fallen by a third, hospital admissions were down by 29 per cent – the fastest weekly drop at any point during the pandemic – and deaths were down by 41 per cent.
In Wales, the Government is considering accelerating the easing of lockdown by lifting "stay home" regulations next week.
Vaughan Gething, the country's health minister, said ministers were debating whether to introduce a "stay local" requirement or to allow unlimited travel across the country. He said the seven-day Covid incidence rate across Wales had fallen to 50 cases of per 100,000 people – the lowest since mid-September.
"As more people are vaccinated in Wales, we may be seeing a faster than anticipated fall in the number of people admitted to hospital," he added.
DfT officials said the new border controls would be part of the review of restrictions by its global travel taskforce, which is due to report on April 12, on whether summer holidays could be saved through vaccination certificates and testing.
Airlines will be expected to check passengers' travel declaration forms and whether they have the right documentation, but the legal onus remains with the passenger. Airport operators warned that the forms would cause major delays if required into the summer.
A DfT source said: "They are not designed to catch people out. It's to put front and centre of people's minds that they should not be travelling at the current time."
Businesses have until March 31 to register for the workplace testing scheme, which will remain free until the end of June.
“These rapid tests will allow positive cases of Covid-19 to be caught quickly, which is crucial in helping businesses protect their workplaces and employees as we cautiously lift restrictions,” said Mr Hancock.