Germany has become the latest European country to ban most travellers from Britain, to try to slow the spread of the Omicron variant.
German nationals and residents will still be allowed to enter from the UK.
They must have a negative test and quarantine for two weeks, regardless of whether they have been vaccinated.
The measures took effect on Sunday evening. France has already introduced similar curbs as coronavirus infections surge in Britain.
The Robert-Koch-Institut (RKI) - a federal health agency - announced the new rules as it classified the UK as a virus variant area of concern, the highest Covid risk level.
Denmark, France, Norway and Lebanon have also been added to Germany's high risk list and travel from those countries will also be restricted.
The decision was made by the RKI on Saturday, when the UK reported 90,418 new Covid cases - following days of record highs. On Sunday, a further 82,886 cases were reported.
London Mayor Sadiq Khan declared a "major incident" in the capital on Saturday due to sharp rise in cases. On Saturday, 26,418 new cases reported - the highest number since the start of the pandemic.
Scientific advisers have warned that England's hospital admissions could reach 3,000 a day without further restrictions.
Although the number of new confirmed coronavirus cases in Germany is lower than in the UK, with 50,968 new cases reported on Friday, the number of deaths following a positive Covid test is rising. Germany reported 437 deaths on Friday.
German health minister Karl Lauterbach said he expected the Omicron variant to unleash a "massive fifth wave" of the pandemic.
He said Germany had to prepare for a challenge "that we have never seen in this form before" and the "more we can push back... the better".
Speaking on broadcaster ARD on Sunday, Prof Lauterbach ruled out a lockdown before Christmas, saying: "There will not be a lockdown before Christmas here. But we will get a fifth wave - we have crossed a critical number of Omicron infections."
The corona-expert council of the federal government - an advisory group made up of 19 members - warned of a growing risk to Germany's "critical infrastructure", saying hospitals, health services and basic utilities could be disrupted if further steps were not taken.
