More than half the workers at twin Alconbury Weald firms where there was an outbreak of coronavirus have been tested for the disease and more tests are being carried out this week.

MM Flowers and AM Fresh - which provide flowers and fruit to the top supermarket chains - said the testing was “progressing well” and that it expected a clearer picture on results by the end of the week.

The firms have been working closely with the health authorities since it emerged that there had been a spike in the number of employees testing positive for Covid-19.

They employ around 550 permanent staff and 300 agency workers between them at the modern purpose-built factory on the former military airfield which is being redeveloped as a major site for business and housing.

A spokesman for the firms said: “On Friday 470 on-site tests were completed, which covers 60 per cent of the site population.

“Further testing is being carried out today and tomorrow (Monday and Tuesday) so we should have an idea about results by the end of the week.”

The majority of the staff live in the Peterborough area and are not thought to pose a risk to local residents, with the factory unit being on a secure site.

MM Flowers and AM Fresh became involved with the health authorities after it was found that 35 people had tested positive for the virus in four months - with the majority, 26 people, being picked up in the three weeks from the end of June.

After the outbreak was discovered the firm took started working in conjunction with Public Health England and local authorities to try to trace the source of infections.

It started to monitor staff and carry out tests as well as adapting processes to meet all government guidelines with the aim of creating a Covid-19 secure site.

Protective measures included social distancing, extensive hygiene practices involving the deep-cleaning of high-touch and high-traffic areas, one-way systems, staggered shifts and the introduction of Perspex screens and face coverings.

People identified as having had close contact with those who had contracted the virus were self-isolating at home.