American travellers are being warned not to travel to the UK.

The US State Department has added the UK to its “Level Four: Do Not Travel” advisory, citing a risk of “very high level of Covid-19”, alongside at least 115 other countries.

Other nations included in the now 150-country-strong advisory - there were previously only 34 destinations on the list - include Canada, France, Israel, Mexico and Germany.

Earlier this week, the State Department said it would advise against travel to more than three-quarters of countries worldwide, citing “unprecedented risk” to American travellers.

Prior to the update, the US State Department had a “Level 4: Do Not Travel” alert, its highest, for just 34 countries across the world, including Kenya, Brazil, Russia and Argentina.

The move “reflects an adjustment in the State Department's Travel Advisory system to rely more on [Centers for Disease Control and Prevention’s] existing epidemiological assessments”.

The advisory is not mandatory and does not bar Americans from travel.

It comes amid speculation that the US will be on the UK’s “green list” when it is revealed in early May, thanks to its advanced vaccine roll-out.

The UK government has given the official nod for international travel to resume on 17 May, under a traffic light scheme, where countries are designated green, amber or red depending on Covid risk.

The “green” countries will carry the lightest restrictions, and won’t require quarantine upon arrival into the UK.