The dramatic development was revealed just moments after Sky News reported that abrdn, the major fund manager, was also considering its position with the organisation.

Aviva announced its decision as the Guardian newspaper reported that a second woman had made a rape allegation against two male CBI co-workers, building on the series of historic serious misconduct claims to have engulfed the body in recent weeks.

"In light of the very serious allegations made, and the CBI's handling of the process and response, we believe the CBI is no longer able to fulfil its core function - to be a representative voice of business in the UK,", Aviva said.

"We have therefore regrettably terminated our membership with immediate effect."

CBI president Brian McBride has previously admitted that a "handful" of its 190,000 members had departed since the crisis began.

They are known to include the British Insurance Brokers' Association.

The potential departure of abrdn would be acutely embarrassing for Mr McBride personally as he currently serves as a non-executive director at the firm.

Sky's City editor Mark Kleinman reported that the board had been debating whether to terminate its status as a CBI member once a CBI-commissioned review of sexual abuse allegations against staff members had been completed.

A source said that alternatively it could decide not to renew its membership when it expires at the end of this year.

A string of blue-chip companies, including Rolls-Royce and Marks & Spencer, have raised public concerns about the crisis.

Last week, the CBI sacked Tony Danker, its director general, after saying it had lost confidence in his ability to lead the organisation amid claims about his personal conduct.

Mr Danker told the BBC this week he had been "thrown under the bus" and said the allegations against him did not merit his dismissal.

He also apologised for making a number of CBI employees "uncomfortable".

Business leaders have lined up in recent weeks to denounce its handling of the crisis, saying it had been too slow to apologise and had erred by appointing an insider, Rain Newton-Smith, as Mr Danker's successor.

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Three employees have been suspended, while a police investigation is under way.

The CBI said this week that the second phase of an inquiry by the law firm Fox Williams would conclude imminently.

"The board will be communicating its response to this and other steps we are taking to bring about the wider change that is needed early next week," the group said on Thursday.