A leading food safety lawyer has called for a wide-ranging investigation following a suspected outbreak of norovirus which led to the closure of nine Wahaca restaurants.

The Mexican restaurant announced that it had voluntarily closed the doors to the restaurants after 205 staff and 160 members of the public became ill.

Speaking to the Daily Mirror a spokesperson for the restaurants confirmed all Wahaca restaurants had been cleaned by specialists and that five sites had reopened.

A spokeswoman said: "We can confirm a number of our employees and customers have reported becoming ill over the past week.

"Initial tests suggest that the cause of this illness was norovirus. Following these reports, Wahaca voluntarily closed nine sites."

Public Health England (PHE) said it had launched an investigation.

Deborah Turbitt, London deputy director for health protection for PHE, said: "Public Health England has been notified of a suspected norovirus outbreak at a restaurant chain.

"We are working closely with environmental health officers and the restaurant chain to investigate.

"We have so far been made aware of 205 staff and 160 members of the public reporting illness, however these are unconfirmed cases.

"Currently, the source of the outbreak is not confirmed and this remains under investigation."

The closed restaurants include Canary Wharf, Covent Garden, Oxford Circus, Soho and White City, all in London.

Michelle Victor from the law firm Leigh Day, an expert in food poisoning cases, said: “This is a very rare case of suspected norovirus as it has affected so many people which appear to be connected across a number of sites.

“We are pleased that the PHE have launched an investigation and would hope that this is a wide ranging investigation into the cause which will inform the public as to the source which at this time remains unclear.”

Those affected are advised to call a GP or the 111 helpline if symptoms persist.