All UK flights to and from Kenya are to be suspended because of increased threats to British planes, the Department of Transport announced today.

The suspension starts from 10pm tonight because the threat level to UK planes has "increased to imminent", the Association of British Travel Agents said.

The move comes after Kenyan security forces were placed on high alert when a senior minister said there was intelligence that al-Qaida terrorists were planning another attack somewhere in east Africa.

Kenya's national security minister, Chris Murungaru, said security measures had been stepped up around foreign diplomatic missions, particularly the British high commission and US embassy.

Around 100,000 Britons holiday each year in Kenya, which was the scene of a devastating car-bomb attack on an Israeli-owned hotel in Mombasa last November. Fifteen people, mostly Kenyans, were killed in the attack. There was also a failed attempt to shoot down a plane carrying Israeli tourists from a holiday resort near Mombasa.