Many charities are underinsured as the employers' liability (EL) crisis continues to bite.
According to The Times the Home Office is to present a report to ministers on the problem later this week, with many charities reporting that premiums have doubled in the past few years.
The British Trust for Conservation Volunteers (BTCV) claims its insurer increased its premiums by 200%. Chief executive officer Tom Flood said: "We pulled the insurance for a month, and told people to stop work. But we're afraid that some may have taken their chances."
Flood told The Times that other smaller charities are not taking out public liability insurance.
John Barton, head of risk management at Cancer Research UK, said the cost of its cover had soared by 200% in the past two years. He said: "None of these areas has got bad claims experience."
He called for a mutual insurance scheme to address the problem. Zyen, a consultancy that is carrying out a feasibility study into this, is due to report in July.
An ABI spokesman said: "We need to get the best possible handle on the risk-management systems of charities, but some could do a lot more to reduce the risks."
