Disabled people and carers have been caused “fear and distress” after an internet forum they use was taken down after disability assessment firm Atos Healthcare threatened to sue for libel.

Atos said the forum, run by carers campaign group Carer Watch, had carried “false and malicious allegations” about the company and its employees.

The forum’s internet host company shut the site without warning, a Carer Watch spokesperson said. The organisation has still not been told why Atos has threatened to sue for libel.

In a letter to the Atos legal team, Carer Watch said members had been phoning forum organisers in tears because of the fear and distress caused by the site’s suspension.

However, it said it could not contact members whose contact details were lost when the site was shut.

“We are in the dark and that is why we contacted Atos,” a Carer Watch spokesperson told Community Care. “By all rights they should have contacted us first and any possible libellous comments would have been removed immediately. Our members, who we’re currently unable to reach, are our priority just now.”

An Atos spokesperson said: “While we fully support the right of people to express their opinions, it is our duty to protect the reputation of our employees and company against false and malicious allegations.

“In such circumstances, we will look to take any necessary steps to ensure that these unsupported claims are addressed swiftly and appropriately.”

Atos is contracted by the Department for Work and Pensions to carry out medical assessments of people applying for employment and support allowance, the replacement for incapacity benefit. Last month, it was criticised by MPs for “unacceptable” failings, including overbooking appointments for assessments and the assessments being carried out at centres inaccessible to disabled people.