Yes, there are broadly two different motivations. For some people, absolutely, they see it as a way to becoming a police officer, although they do recognize that recruitment has dried up and is likely to be very slim for the future. But secondly, also, many of them do it out of a sense of public service. A large number of special constables are very happy in another career but do this because they want to add something to their community.
On February 14th, 2013. See this statement in context.