Travellers detained in quarantine hotels will be told later today when they will be released, a senior official said.
Jonathan Mogford, who is responsible for the managed quarantine service at the UK Health Security Agency (UKHSA), was questioned about reports some people were fleeing the hotels after the red list was scrapped in England at 4am.
Mr Mogford told the Commons Transport Committee: “The standard practice has been that if you have started hotel quarantine, you need to complete it.
“For this de-listing, where Omicron has moved unexpectedly fast, we want to release people early.
Mr Mogford told the committee there have been “unprecedentedly high rates” of positive Covid cases among travellers quarantined from the 11 red list countries, which included South Africa and Nigeria.
He said latest figures suggest “nearly 5% of people in the hotels are positive”.
There have been “roughly 5,000 guests through in this round of red listing”, he said.
His comments indicate that around 250 of those people tested positive.
Asked about complaints over poor food, he said: “We share the concerns of what we have seen on social media and those have been picked up with the hotels directly.”
UKHSA chief executive Dr Jenny Harries said travel restrictions have “a time and place” in protecting public health.
She told MPs that the red list was resurrected last month “as a delaying tactic”, giving the UK “time to prepare” for the Omicron variant.
Travellers entering the UK must take a pre-departure test and self-isolate until they receive a negative result from a post-arrival test.
Committee members and Labour former cabinet minister Ben Bradshaw claimed Transport Secretary Grant Shapps told him the travel testing regime was “pointless”.
He said: “The health minister said to me in the House yesterday that he thought they were pointless and the Transport Secretary told me in the division lobby last night that he thought they were pointless too.
“Someone is obviously keeping them in place, who is keeping them in place?”
Dr Harries replied: “It’s not for us to make decisions. We give advice to ministers and I can’t speak on behalf of either of the ministers that you have just mentioned.”
Downing Street insisted the measures were not “pointless”.
The testing requirements “remain important in helping to prevent additional Omicron from seeding in the United Kingdom”, the Prime Minister’s official spokesman said.