When a university lecturer decided to help improve his students' climbing skills by constructing an artificial rock face, he never imagined 40 years on his brand would be known world-wide.

The climbing wall, manufactured in 1964 on the Leeds University campus, was the first of its kind and became an instant hit with students.

Today it is still widely used on the campus by keen climbers and beginners who want to learn the basics.

For its inventor, Don Robinson, the wall proved such a success that he decided to set up his own climbing wall manufacturing business in 1975.

Now, almost 30 years on, DR Climbing Walls Ltd, in Pool-in-Wharfedale, is thriving and Mr Robinson has travelled the world to put together walls which have been ordered from his company.

The super-fit 77-year-old, who was the oldest competitor in last year's Burnsall Fell Race, is still spearheading the business.

"The walls have been very successful," said the former Leeds University physical education lecturer. "If people tried out that initial wall at Leeds University they would be able to teach themselves to climb pretty quickly.

"What we found was that people were going from using the wall at the university and tackling climbs outdoors that had rarely been completed and they re-wrote the rules really."

Mr Robinson said the walls are designed for the company by a specially selected team.

They can feature different inclines, can have different hold and grip positions and can be constructed at different heights and widths.

They are constructed from a skeleton of scaffolding and the wall can be made from materials ranging from plywood to concrete, depending on the environment it will be placed in.

Mr Robinson has flown around the world to personally deliver the walls and has been to Australia, New Zealand, New York and Singapore on business.

He even flew to help put together one of the walls which had been ordered by a sheikh in Dubai.

Mr Robinson said each wall cost between several hundred and several thousand pounds to buy from the firm.

He said after the wall had been designed, the company bought in the required materials for that specific order and put the wall together either in Pool or at the location.

Many orders for the climbing walls have also been taken from institutions in the UK, including schools, universities and the Army.

Mr Robinson said over the past decade more climbing wall manufacturers had been established and the market was more competitive.

But he said he was still optimistic about the future of the company, which employs around eight full-time staff.

He said it was difficult to state the profits made by the business because orders fluctuate each year but, on average, ten walls are sold each year.

"It's quite a complex exercise making it happen but it is an enjoyable one and that's why we are still going," he said.