Mike Tildesley, a professor in infectious disease modelling at the University of Warwick, said: “This is clearly going to be big news, but the key thing is that human infections with H5N1 are really rare and they almost always occur as a result of direct, long-term contact with poultry.

“There has never been any evidence of sustained human-to-human transmission of H5N1, so at present I wouldn’t consider this to be a significant public health risk.”

Prof Isabel Oliver, the chief scientific officer – transition lead at the UK Health Security Agency, said: “While the risk of avian flu to the general public is very low, we know that some strains do have the potential to spread to humans and that’s why we have robust systems in place to detect these early and take action.

“Currently, there is no evidence that this strain detected in the UK can spread from person to person, but we know that viruses evolve all the time and we continue to monitor the situation closely.”

She added: “We have followed up all of this individual’s contacts and have not identified any onward spread. It remains critical that people do not touch sick or dead birds, and that they follow the Defra advice about reporting.”

Experts also reassured the public that there is no risk from eating poultry or eggs.

Prof Ian Jones, a virologist at the University of Reading, said: “Despite the current heightened concern around viruses there is no risk to chicken meat or eggs and no need for public alarm.”