Council chiefs said since the scheme began a year ago its buses have ferried more than 500,000 passengers in and out of historic Durham city.

It operates from three edge-of-city car parks on key arterial routes.

To celebrate its first year, passengers who use the service this weekend will receive a ticket to travel on the service free on a Saturday in February.

The county council's cabinet member for transport, Councillor Bob Pendlebury, said: "The level of usage during the past 12 months has shown that its early popularity was no flash-in-the-pan.

"While it is proving especially popular with commuters and shoppers, visitors are also finding the service convenient.

"It has also led to people visiting the city from north Northumberland, North Yorkshire and Cumbria who said parking problems had previously put them off coming."