British tourists in Tunisia have been advised to leave the country amid fears of a fresh terror attack following the atrocity in Sousse.
The Foreign Office has warned against all but essential travel following intelligence that a terrorist attack is “highly likely”.
Tour operators are arranging extra flights to ensure holidaymakers can leave, the government said.
UK authorities have been working with their Tunisian counterparts since the beach massacre that claimed the lives of 30 Britons.
But despite increased security since the shootings the Government said the extra measures did not go far enough.
In updated travel advice, the Foreign Office said: “ Since the attack in Sousse, we have been working closely with the Tunisian authorities to investigate the attack and the wider threat from terrorist groups in Tunisia.
“Although we have had good co-operation from the Tunisian government, including putting in place additional security measures, the intelligence and threat picture has developed considerably, reinforcing our view that a further terrorist attack is highly likely.
“On balance, we do not believe the mitigation measures in place provide adequate protection for British tourists in Tunisia at the present time and we have therefore changed our travel advice accordingly.”
Holidaymakers should contact their tour operators about returning to Britain and independent travellers should make their own arrangements to leave, the FCO said.
Foreign Secretary Philip Hammond said the Government did not have intelligence about any specific threat.
He told the BBC: “While we do not have any information suggesting a specific or imminent threat, since the attack in Sousse the intelligence and threat picture has developed considerably leading us to the view that a further terrorist attack is highly likely.”
Between 2,500-3,000 British tourists are believed to be in Tunisia and around 300 independent travellers.
The Association of British Travel Agents (Abta) urged people due to travel to Tunisia to contact the company they booked through.
It said: “ For anyone due to travel, you should be aware that travelling out to Tunisia at this time is likely to invalidate your travel insurance policies. Most insurance policies will still provide cover for travellers in a country at the time of Foreign Office advice change.
“ Those with holidays booked within the next 48 hours to Tunisia are advised to contact your travel company to discuss available options. If you have booked a package you will be entitled to a refund or alternative holiday.”