Where does the so-called Golden Triangle in Norwich stop and start - and just who were these people called Unthank? Derek James takes up the story.

It was a rather tall wall at the junction of Clarendon and Unthank Road in Norwich which caught the imagination of a curious man who then embarked on a journey of discovery... one that has now resulted in a local best-selling book.

Thirty years ago Clive Lloyd, a project leader in Cell Biology at the John Innes Centre, bought a house on the busy road and was told that the wall was opposite the former site of the Unthank's house and was the last vestige of the vast family estate.

'Occasionally I would hear this urban myth and repeated as if it were fact and I became fascinated with it,' said Clive, now retired.

Three decades on and with an awful lot of painstaking research, he has written a fascinating book called Colonel Unthank and the Golden Triangle: The Expansion of Victorian Norwich and it is a wonderful addition to local history.

The story of the development of the city's much-loved Golden Triangle is interwoven with the lives of three generations of the Unthank family, their estate and the road named after them forms the backbone of this much-sought after area.

By tracing the ownership of the wall the development of the Golden Triangle starts to unfold and the story starts with the Unthanks.

So who were they and just where did they come from?

William Unthank senior, who had arrived in Norwich from Durham in the 18th century, was the son of Robert Unthank from a village called, you've guessed it, Unthank in Northumberland.

Now William was a clever and astute businessman and between 1758 and 1790 he ran a number of businesses in St Stephen's. He also rented coaches and his home at 2 Rampant Horse Street, was convenient for the inn where stage coaches to London departed. It was a busy place – and still is.

His son, also William (1760/1837) trained to be a solicitor and in 1786 became partner to William Foster moving to Old Bank of England Court in Queen Street, Norwich.

Fosters is now one of the major law firms in the city.

Young William was a started to acquire property and land. It was said he owned around 2,500 acres as well as land in the parishes of Eaton and Heigham – where this story is based – along with considerable holdings across Norfolk.

He married Ann Mary of Southwold. They had seven sons and two daughters. They moved to the parish of Heigham just outside St Giles' Gate in 1793.

It was one of the boys, Clement William, who received the lion's share of the Unthank estate when his father died in 1837 aged 77.

Clement fell in love with Mary Anne Muskett of Intwood Hall, a few miles south of Norwich, and it is said that he rode his horse along a sandy back lane to visit her. That lane became Unthank Road.

They married in 1835 and lived on a large estate, somewhere in Heigham, until moving to Intwood Hall.

In extraordinary details and illustrated by fine photographs author Clive follows the story of the Unthank family over the years and how the land they owned was developed.

Not one but three members of the family were known as Colonel Unthank:

Clement William (1804-1884) who, as Deputy Lieutenant of Norfolk, was involved in raising volunteers for the Crimean War.

His son CWJ Unthank (1847-1936) was a captain in the 17th Lancers and in later life was known as the Old Colonel.

And his son John Salisbury Unthank DSO, MC (1875-1959) fought in both the Boer and the First World War.

The Rev AJ Nixseaman, vicar of Intwood, from 1956 to 1967, wrote that when the bluff old soldier stood up to take his mackintosh off in church, the congregation sitting behind him stood up as well. A mark of true respect.

Clive takes a close-up look at the break-up of the Unthank estate and then invites us on a journey around this wonderful part of the city which has become such a happy and fashionable home for thousands.

From the Heigham Lodge Estate across to Newmarket Road and so much more. Even if you don't live there it will encourage you to visit. Perhaps visit The Plantation Garden or even The Unthank Arms.

As for that wall.... best you buy the book.

Colonel Unthank and the Golden Triangle by Clive Lloyd costs £10 and is on sale at Jarrold and at City Books, Davey Place, Norwich. Clive also writes monthly articles on the history of the city at colonelunthanksnorwich.com