Approximately 50,000 British holidaymakers currently in Florida should avoid unprotected sex for the rest of the summer holidays because of the risk from Zika virus, according to government advice.

An outbreak of four mosquito-transmitted cases yesterday prompted Public Health England (PHE) to advise pregnant women to consider postponing non-essential travel to the southern US state.

But for the large numbers of British tourists already there, the presence of the virus means that they should refrain from sex without a condom for eight weeks, even if neither partner has symptoms of the disease and there is no prospect of a pregnancy.