If you look on http://www.raib.gov.uk you should be able to find reports relating to accidents on heritage railways, which often use volunteers. Although the RAID does not apportion blame, some of these cases may have gone to law and a bit of Googling should provide further info.

Princes Trust and a college in Bristol fined over exposing volunteers to asbestos (reported around February 2009). BTCV (now The Conservation Volunteers) fined £500 for unsafe system of work when volunteers were building a footbridge in Scotland (around 2005/6 I recall) Volunteer drowned in a water training exercise, cannot find the detail to hand but possibly one of the first aid charities involved, fine was over £100k HSE made a point of clarifying that for teh purposes of RIDDOR volunteers were 'members of the public' which does alter the mindset of reporting for many charities. Could also contact Charities Safety Group (www.csg.org.uk) in case they have further information from their members Andy

RSPB - Interested in your comment that the HSE regards volunteers as "members of the public" for the purposes of RIDDOR. This seems to be at odds with other "comment/guidance" that clearly sets out that volunteers are regarded as employees and should be subject to the same management and control, receive the same "information, instruction, training & supervision" as full time employees. Employers' Liability insurance policies recognise that for many/most volunteers the "master/servant" relationship that underpins civil duty of care exists for them in the same way as for employees. The defintion of employee in such policies is generally (99% of policies) extended to include volunteers. Phil