The UK Health Security Agency (UKHSA) have said the virus that causes polio has been detected in a worrying number of sewage samples in London.

The disease which was common throughout the UK in the 1950s was eliminated by 2003.

It is believed the latest strain may have been imported to London by someone who was recently vaccinated overseas with a live form of the virus.

Although the risk is low, parents have been advised that they should ensure their children have been fully immunised against the disease.