How would I go about finding out why and by who somebody was put into the workhouse?

The lad I am interested in is John Leach aged 9 Pauper on the 1851 census. He appears to be there on his own and I can find no sign of his parents or any siblings he may have had anywhere.

Thanks
Jo x

A strarting point would be the Poor Law Union and Workhouse website.
http://www.workhouses.org.uk/index.html?Gloucester/Gloucester.shtml

Thanks for the advice!

Jo x