The sudden closure of a college for vulnerable people was due to the serious abuse of residents by staff, the health and social care regulator has revealed.

The Care Quality Commission (CQC) detailed a number of shocking allegations at Westgate college for deaf people and the Road Project, in Margate, Kent, including residents being pushed, hit and humiliated. In one case a resident allegedly had a hot cup of tea placed on their arm.

The service was run by the John Townsend Trust. As well as deaf people it also provided for those with communication, physical or learning disabilities. It closed with immediate effect last December.

The CQC said on Tuesday that it took legal action the same month requiring residents to be moved for their own protection but – due to legal reasons – can only now reveal what it did and why.

Andrea Sutcliffe, chief inspector of adult social care at the CQC, said: “What we saw at Westgate college for deaf people and the Road Project – and what was reported to us – were shocking examples of institutionalised failings and abuse.

“Residents were physically harmed by the very people who should have been caring for them and the leadership within the John Townsend Trust did not take sufficient steps to prevent this, or to tackle a culture where people in vulnerable circumstances were not protected.”

The regulator said it first received safeguarding alerts about the service in June 2014. Sutcliffe said the CQC had to balance closing the service with “the difficulties involved in finding alternative placements for them at short notice”. At an unannounced inspection in October 2014, it was reported that, after a resident ripped their T-shirt, a member of staff hit the resident with it and told them that their activities would be withdrawn.

Another unannounced inspection the following month uncovered more abuse, including residents being ridiculed for their physical and learning disabilities. As a result, a number of staff members were suspended, some of whom were later dismissed.

Further serious concerns were raised in July 2015, including an allegation that a resident had had a hot cup of tea placed on their arm and was then goaded by a staff member. There was a separate allegation that a staff member had grabbed a resident around the neck and pushed their head down.

On a later visit inspectors found serious medication errors and that vulnerable residents were left unsupervised in a swimming pool with no lifeguard on duty. In some cases, police were notified but no charges were brought due to insufficient evidence.

Dan Scorer, head of policy at the learning disability charity Mencap, said: “These failings should never have been allowed to happen. We must find out immediately the role that all agencies played and whether the failings at this service could have been identified, acted on earlier and stopped.”

Labour said it was deeply concerning that such abuse was happening five years after the Winterbourne View scandal.

Barbara Keeley, shadow minister for care, carers and older people said: “

“Ministers need to provide urgent assurances that this kind of abuse is not widespread and that action is being taken to protect the welfare of vulnerable people who receive care.”

A Department of Health spokesman said: “This report uncovers shocking abuse and it is absolutely right that our tough new inspection regime has stepped in to put an end to it.

“We want care in this country to be the safest and most compassionate in the world – the CQC has once again proved the vital role it plays in making this a reality.”

• This article was amended on 6 April 2016 to insert a missing word into the quote from the Department of Health spokesman.

