A map of Norfolk with surnames and twitter names rather than cities and towns reveals some of our oldest families and newest communications, writes Rowan Mantell

It's a sea of Smiths, from King's Lynn to Yarmouth and Cromer to Thetford. But travel up to the real sea and as you crest the ridge before Salthouse the waves of Smiths that cover most of Norfolk suddenly shift and an island of Holman emerges. And almost as far north as you can go in Norfolk, so north that just about the only land further north is the North Pole, lies an outcrop of Southerlands.

A fascinating interactive map of Britain has been produced by academics from University College, London.

Instead of showing towns and roads, this is a map of our most common surnames. At first there are few surprises. Across England, Smiths reign supreme, giving way to Joneses in Wales and MacDonalds in Scotland.

But look closer, focusing down from countries to counties to towns and villages, and up in a pocket of North Norfolk the old names begin to show through. Drill down through the map to the third most common surname in the Overstrand and Northrepps area, near Cromer, and discover a sturdy patch of Gurneys.

Edmund Perry of the Norfolk Family History Society said the Gurney's ancestors fought alongside William the Conqueror. More than 140 years ago John Gurney, a Norwich Quaker renowned for his honesty, founded a bank, which later became part of Barclays. Prisoner reformer Elizabeth Fry was born a Gurney and the Norfolk villages which became home to generations of the illustrious old family now show up on this very modern map.

The second most common surname between Wells and Stiffkey is Frary. Just along the coast in Cromer it is Davies. Between Stalham and Sea Palling it is Grimmer.

Not that there is anything grimmer about this beautiful stretch of coast, it is just likely to have more Grimmers than anywhere else in the world.

On the surname map Filby has moved 20 miles to the north west and is no longer a village but the third most common surname in the Erpingham and Aldborough area, north of Aylsham. The village, near Yarmouth, is said to have got its name from a Viking called File, who settled here more than 1,200 years ago. Perhaps his descendants moved to new land (but just across the Bure rather than over the North Sea.)

In north west Norfolk they continue to do different, down to the second most common names (Hipkin and Howling) but across the majority of the county Smiths are followed by Wrights and then Clarkes.

Mr Perry explained that these are all derived from occupations. Smiths worked with metal, hence blacksmiths and silversmiths. 'It comes from smite,' said Mr Perry. 'Wrights made things, often from wood, like wheelwrights, and Clarke is probably from the same root as clerk, so Clarkes are learned people!'

He inherited his interest in genealogy from his mother, whose family they traced back to 18th century Norfolk.

Another ancient Norfolk surname revealed by the interactive internet map is Foulger, which runs along the Norfolk-Suffolk border. The 1881 census echoes the finding – there were more Foulgers in Norfolk and Suffolk than in all the rest of the country put together.

Mr Perry said: 'It's an Anglo Saxon name meaning follower or attendant – these were free men who didn't have their own land and worked for someone else.'

He said another specifically Norfolk name is Kett and there were also the Windhams of Felbrigg, and the LeStrange, LeNeve and LeGrice families which can all trace their Norfolk roots back many centuries.

'For family history research, it is the unusual names, the names peculiar to a place, rather than the common names, which are the most interesting,' said Mr Perry.

And Norfolk suddenly becomes much more diverse when another layer of the interactive map strips away the ocean of Smiths, Wrights and Clarkes to reveal the most popular Twitter names – and Mucklow, Stothard, Honeybone and Wisdom swim into focus.