Ancestry.co.uk, UK based genealogy website initiated a project to digitize all available public records in London city over last 400 years. This brings all the data scattered throughout London into one single repository. Public records include birth registration, death records, wills, parish registers, marriage records etc. The entire project is estimated to have 77 million records over 400 years.

This could be place where you could start your family tree.

Source: [http://www.telegraph.co.uk/news/uknews/5055524/Internet-breakthrough-could-allow-millions-to-trace-ancestors-to-16th-Century.html|Telegraph article]