Foreign Secretary William Hague condemned the bombing of a bus in Jerusalem today as a "callous and disgusting act of terrorism".
One woman was killed and more than 20 other people were injured in what Israeli police said was an attack by Palestinian militants.
Mr Hague said news of the explosion - which comes against the backdrop of mounting violence after two years of relative peace - was "shocking and deeply distressing".
"We are urgently seeking further information about the cause of the explosion, which has caused appalling death and injury," he said in a statement.
"I send my sincere condolences to all those who have been affected and my sympathy to the people of Israel as they come to terms with this news.
"This appears to have been a callous and disgusting act of terrorism directed against innocent civilians which I condemn unreservedly.
"I would like to express the UK's unwavering support for the people of Israel in the face of such horrific acts."