Conditions at Harmondsworth Immigration Removal Centre near Heathrow have come under further scrutiny after the facility received a zero out of five food hygiene rating.

The London Borough of Hillingdon conducted the inspection at the largest immigration centre in Europe on September 9 and gave it the lowest possible rating.

The inspection found that ‘urgent improvement’ was necessary in the facility’s hygienic food handling and ‘major improvement’ was required in the cleanliness and condition of facilities and buildings.

‘Urgent improvement’ was also needed for the management of food safety at the facility off the Colnbrook bypass near Heathrow.

A Home Office spokesman said: “The circumstances which led to this rating were unacceptable and we have ensured that our service provider has taken immediate steps to improve the food hygiene standards at Heathrow immigration removal centre.

“External inspectors have agreed that significant improvements have already been made. We are also strengthening our own checks on catering provision and have made it absolutely clear to our contractor that this must not happen again.”

The detention centre holds over 500 men including asylum seekers and foreign offenders awaiting deportation.

A spokesman for MITIE Group, who run the centre through their Care and Custody division on behalf of the Home Office, declined to comment on the rating.

The food hygiene rating comes just a few months after a critical report of the facility by the chief inspector of prisons, Peter Clarke.

In his report Clarke said: “Overall, while this report describes some good work, it highlights substantial concerns in most of our tests of a healthy custodial establishment.

“While the state of drift that we described in our last report has been arrested and the direction of travel is now positive, it is unacceptable that conditions were allowed to decline so much towards the end of the last contract.

“The Home Office and its contractors have a responsibility to ensure that this is not allowed to happen again.”