In my case a volunteer that works for a charity that supports the ambulance service. We wear ambulance service uniform, drive a marked FRU and are trained by the ambulance service. We do a lot of standby sat in the cars where control think their might be a job and if we do get get given a job try to stick to the 3 principles of first aid, Preserve Life, Prevent the condition worsening and promote recovery. www.first-response.org.uk is my charity but there are many other responder organisations round the country.