One person in England has died linked to the ongoing E. coli outbreak, the UK Health Security Agency has said.

The person died in May and had underlying health conditions, the agency said.

Another person in England, who also had underlying health conditions, died within 28 days of being infected with the current strain, but the UKHSA says information suggests only “one of these deaths is likely linked to their STEC infection”.

The E. coli outbreak is thought to be caused by some supermarket sandwiches containing salad leaves.

All the cases reported so far developed symptoms before 4 June and the number of cases being reported is now falling, offering hope the outbreak may have ended.

Several food manufacturers removed some of their products from shelves as a precaution.

The Food Standards Agency said lettuce is the likely source, based on tests.

Darren Whitby, Head of Incidents at the FSA, said: “Earlier this month, we confirmed that several sandwich manufacturers had taken precautionary action to withdraw and recall various sandwiches, wraps, subs and rolls after food chain and epidemiological links enabled us to narrow down a wide range of foods to a type of lettuce used in sandwich products as the likely cause of the outbreak.”

He said work continues to confirm this so that actions can be taken to prevent a re-occurrence.

“This remains a complex investigation and we continue to work with the relevant businesses and the local authorities to ensure necessary steps are being taken to protect consumers,” he said.

As of 25 June, there have been 275 recorded cases of E. coli (STEC) O145 across the UK.

The overall number of people affected could still rise because some samples from patients have yet to be tested, experts say, although rates are slowing.

Data from 249 cases shows half needed hospital care.