New rules that see all British and Irish citizens and UK residents arriving in England from red list countries needing to quarantine in a hotel for ten days have come into force.
The list of 33 countries includes much of South America, Portugal, South Africa, the United Arab Emirates and elsewhere.
The new regulations, which aim to stop Covid-19 variants entering the country, apply to arrivals who have been in one of those places in the past ten days.
Travellers will have to pre-book and pay £1,750 to spend ten days quarantining in government-sanctioned hotels.
The figure covers the cost of the hotel, transport and testing.
The government said last week it had struck deals with 16 hotels so far, providing 4,963 rooms for the new quarantine system, with a further 58,000 rooms currently on standby.
“The rules coming into force today will bolster the quarantine system and provide another layer of security against new variants at the border,” said health secretary Mat Hancock.
Scotland will require all arrivals travelling by air, regardless of their point of origin, to undergo a similar quarantine.
People travelling from red list countries to Wales and Northern Ireland will be required to book and pay for quarantine in England, as neither destination currently has any direct international flights.
Any passenger required to stay in a quarantine hotel in England needs to reserve a room online in advance using a government portal.
As the new rules come into force, Unite is warning that the government guidelines on quarantine hotels fails to adequately protect workers from being exposed to Covid-19.
The Union, which represents thousands of workers in the hospitality and hotel sector, said rules were not tight enough.
Guests will be allowed access to fresh air outside, escorted by a security guard, whereas in Australia, the view is that staff should not be put at risk by escorting people outside, for example.
There is also no guidance on the timing of meal deliveries, potentially leading to cross-infections between guests as room doors are opened at the same time, the union said.
Unite warned last month that the plans for quarantine hotels must ensure that there is complete Covid-19 security for staff working in them.
Unite hospitality organiser, Bryan Simpson, said: “The revelations that the guidelines for preventing the transmission of Covid-19 are far inferior to those in Australia are deeply alarming for hotel workers.
“Once again, the government has been found guilty of prioritising headlines over the safety of workers.
“It must not be ignored that workers are in as great a danger of transmitting the virus between each other as being exposed to it from quarantining passengers.
“Unite will be assisting our members on a hotel-by-hotel basis.
“If safety measures are insufficient Unite will demand immediate changes.”