The deputy prime minister's surname could soon be extinct, along with a host of other once common names, according to a genealogy website.
Clegg could soon follow surnames like Chips, Hatman, Rummage, Nithercott, Raynott, Temples, Southwark and Woodbead into obscurity, according to the research.
Ancestry.co.uk compared surnames from the 1901 censuses with those from modern records and found that tens of thousands that have disappeared.
William was the 374th most common surname in 1901, but has fallen to 12,500th today, said Ancestry.co.uk
And surnames such as Clegg, William, Cohen, Kershaw, Sutcliffe, Butterworth and Greenwood are at risk of going the same way, the study said.
Many of the surnames which have vanished were anglicised by their owners, including immigrants who changed their name to avoid complications with the spelling of their foreign names.
The First World War also played a part in wiping out some names as specific battalions suffered mass casualties during the conflict, with towns or villages losing a generation of young men, said the report.
Miriam Silverman of Ancestry.co.uk said: "As a nation we've become more interested in where our names come from and what they mean. To many, a name is more than just a label - surnames are often steeped in history and identity, so nowadays a rare surname is something to be treasured rather than changed."
09 May 2011