British experts have urged people not to panic after health officials said a potentially fatal Sars-like virus can transmit from human to human.

The World Health Organisation (WHO) made the comments after a French man developed the illness after sharing a hospital room with a patient suffering from novel coronavirus.

The infectious disease has killed at least 18 people globally, including two people in the UK.

Health officials in the UK have been advised to be vigilant for severe unexplained respiratory illness in anyone who has recently travelled in the Middle East, as well as any unexplained clusters of such illness.

Professor Peter Openshaw, director of the centre for respiratory infection at Imperial College London, said: "We are right to be concerned about the reporting of transmission from person to person, but there is absolutely no reason to panic.

"Human-to-human transmission has now been documented but this is not a great surprise and the virus seems relatively hard to transmit.

"The 'super-spreading' events, in which one person infects several dozen people at a time (as was seen with Sars coronavirus), do not seem to be happening with this coronavirus."

Professor John Watson, head of the respiratory diseases department at Public Health England, said: "There have been no new cases of novel coronavirus in the UK since February 2013 so the total remains at four."