Interesting site that gives the description and worldwide distribution of your surname my surname is rated 4,363rd most common surname in the world http://forebears.co.uk/surnames all clever stuff and quite informative
117th most common surname in the world Most common name in England, America, Australia, Scotland and Canada.
Mine is 144,879th most common name...Most prevalent in the USA and most density in Australia..I know that my name originates from Cornwall.
Smith is most certainly the most common name in the UK. For the record the longest name in the UK is Smiles..
You're the first person I've ever heard of with the surname 'Diddles' I'd put you much lower down than that. Out of interest what's first? Last time I looked it was Patel, the world's most common surname.
Wouldn't be surprised if Muhammad was the most common first and second name! Singh and Lee, I would also expect to be high up there