With the 21st Bristol half marathon being run tomorrow, it is worth recalling the humble origins of this event.

Runners who assembled for the inaugural race in 1989 would barely recognise the event into which it has grown. Now the whole city comes to a halt, roads are closed and hundreds of city officials and volunteers are mobilised to ensure that the 16,000 entries are given a hassle-free day.

For competitors in the 1989 event, which replaced the Bristol marathon after that became prohibitively expensive to stage, the challenge was not just to complete the 13.1 miles.

"The 1989 race started and finished on the Downs and none of the roads were closed to traffic," said Ray Jaeckels, who was the original race director and is now technical director to the event.

"We had about 1,000 runners and they headed straight down Bridge Valley Road and left along the Portway into Cumberland Basin, and then took in Hotwells Road, Coronation Road and into Bedminster, then back along North Street to Ashton Gate and through a series of tricky underpasses into Ashton Court. There was the long climb up Ashton Court and then back into Clifton over the Suspension Bridge with the finish up Ladies Mile.

"You have to remember on those days the traffic situation was very different. There was no Sunday trading and the stats show us that the volume of traffic has increased by around 27 per cent since then.

"There was far less traffic on the roads than today, but even without that you could not use that course today with the amount of runners we have.

"Obviously it was great to have the start and finish on the Downs with all the space up there, but now you have to have to consider what would happen if there was a torrential downpour. If that happened the grass area would become a quagmire, as happened at Bath the other year."

Jaeckels and Bristol's Great Western Runners club were the volunteer organisers of the event in the early years, with the race HQ at the Welsh Back Health and Fitness Club.

"Interestingly, 98 per cent of the runners were local while just eight per cent of the 1,030 finishers were women," added Jaeckels. "Now we have nearly 50 per cent women in the race, so that has been a dramatic change, while a lot more runners from outside the area enter."

The turning point in the event growing from a strong regional race into one of national importance came in 2001, when it hosted the World Half Marathon Championships, with global stars Paula Radcliffe and Ethiopian Haile Gebrselassie racing to victory.

"Bristol City Council became more involved in 2000 and then took it on the following years," said Jaeckels. "At that point we had grown to 4-5,000 runners and I can remember the club's entries secretary, Pete Hawkins, telling me that he was struggling to cope with the work – on top of his normal day job!

"It needed a change and the following year really kick-started it to a new level."

Finally, can you recall who won the first race? In the days before the Africans took charge, Welsh international Steve Brace claimed victory after Westbury's Declan McGrath led for the first 12 miles, while Bronwen Cardy-Wise was top woman.