Cyclists were caught in a double police operation on the same day, flouting pedestrian restrictions in the city and then riding without lights later that night.

Fifty-one cyclists were given fines for riding in the pedestrianised zones in Cornmarket and Queen Street over three hours – although police officers were too busy to stop them all.

And later on Wednesday night officers were also catching cyclists without lights at The Plain, leaving police frustrated that safety laws were still being ignored.

Bike riders are not allowed to cycle down Cornmarket and Queen Street between 10am and 6pm and those who were caught on Wednesday were given £30 fines.

Pc Dawn Evans, one of the officers in Cornmarket, said: “We love the fact that people cycle in Oxford. We want people to be cycling around the city but they’re going to have to stick to the areas where they can do so. The restriction is there for safety reasons.”

One cyclist who got caught by the police, said: “The fine is a bit steep but it’s fair enough.”

We stood independently at Carfax for 20 minutes on the same day and counted 10 cyclists riding into the restricted zones.

One of them must have got back on to his bicycle in Queen Street after passing the police.

And yesterday, about half of cyclists spotted cycling along Botley Road during a 10-minute survey were without lights in the early morning gloom.

Mark McArthur-Christie, former chairman of the Oxford group of the Institute of Advanced Motorists, said: “There is still a group of cyclists who don’t follow the rules. But I think the numbers of them are decreasing.”

Sushila Dhall, of Oxford Pedestrians’ Association, said cyclists were putting walkers in danger.

She said: “I’ve certainly seen quite a few people cycle down Cornmarket and Queen Street. It makes pedestrians feel unsafe because it only takes a moment for a toddler to run out or for a pedestrian to change direction.

“There’s a small number of cyclists who persistently ignore the rules. What we lack in Oxford is common courtesy between road users.”

But James Styring, of cycling campaign group Cyclox, said: “People shouldn’t cycle down Cornmarket and Queen Street but they need to change the regulations.

“I don’t think it’s a big deal when you think about people who drive while on their mobile phones.

“On Cornmarket there are probably too many pedestrians for any sensible person to want to cycle."