In 1975, archaeologists were growing excited about the Viking-age remains they thought might lie beneath a nondescript York street named Coppergate.

The area was being cleared ready for a new shopping centre. And preliminary excavations had revealed evidence of wooden timbers and pottery that dated from pre-Norman Conquest times.

The recently-formed York Archaeological Trust put together an exhibition – The Viking Kingdom of York – at the Yorkshire Museum. Then, as other buildings were demolished, they began to extend their excavation. They even came up with a fund-raising idea: visitors, for a small fee, could watch archaeologists at work from a walkway beside the dig.

Then it was decided the whole thing should be more ambitious. A bit of celebrity gold-dust was wanted. “Who is the most famous archaeologist in the country?” someone asked.

No-one, not even the Trust’s founding director Dr Peter Addyman, seemed to know. But then Dr Addyman had a brainwave. Magnus Magnusson, presenter of the hugely popular TV quiz show Mastermind, was an Icelander and proud of his Viking roots, he said.

“He’ll do,” said someone. “How do we get hold of him?”

It so happened that Magnusson was in York. Dr Addyman met him for coffee, and the rest is history.

Magnusson recorded a short BBC programme on Viking York. It went out late one night – and the following morning Dr Addyman received a telephone call from a Lancashire motor-engineering supremo by the name of Ian Skipper. Mr Skipper wanted to come and see the Coppergate dig for himself.

“When?” Dr Addyman asked. “Now!” came the reply. And sure enough, later that day, a Rolls Royce turned up on site.

Mr Skipper emerged, ‘immaculately turned out (and ) accompanied by his his elegant wife and two delightful daughters’, as Dr Addyman recalls it.

Mr Skipper insisted on descending to see the dig there and then. And then he offered to help – not with a cheque, but by sending over a team of consultants, who proceeded to turn the dig into a word-famous tourist attraction.

This story is told by Dr Addyman in his new book York Archaeological Trust: 50 Years On, published this month on the Trust’s 50th anniversary.

As the Trust’s founding director, no-one was in a better position to tell the story than Dr Addyman. His wonderful account, lavishly illustrated with archive photographs, covers the whole 50 years, from the founding of the Trust in October 1972 to the opening of the Jorvik Viking Centre in April 1984 and the trust’s plans for a Roman version of Jorvik beneath Rougier Street today.

For those interested in how Viking-age York became the talk of the modern world, it’s a must.

York Archaeological Trust: 50 years On by Peter Addyman is available, priced £18.50 hardback or £12.50 softback, from the Jorvik shop or online from jorvikshop.com/books