Shoppers have been warned to expect long delays on Oxford's roads this Christmas because of the city's "bastardised" transport policy.

Cars in St Giles in Oxford City councillors have predicted widespread congestion with motorists searching for one of about 600 free on-street spaces which will be available from 6pm on Thursday.

They claim Oxfordshire County Council's decision to introduce the free spaces will have a damaging effect on traffic flow and the income generated at city centre car parks.

But county councillor David Robertson, the authority's cabinet member for transport, said the changes should make Oxford a "thriving, interesting place".

County Hall has decided to waive charging at on-street sites, such as Broad Street and St Giles, after 6pm on weekdays and all day on Sundays, at a time when the city council has increased car parking charges to generate an extra £536,000 a year and encourage use of public transport.

The county council will lose an estimated £750,000 in income as a result of the six-month pilot and a further £700,000 by ending parking charges at its Thornhill and Water Eaton park-and-ride sites.

Meanwhile, county transport officers are finalising plans for patrolled Controlled Parking Zones across the city -- with residents charged a fee to park outside their homes.

The move aims to discourage commuters parking in areas such as Headington and Marston.

Liberal Democrat city councillor Stephen Tall said: "You can't offer free parking and then claim to cut congestion -- this is environmentally unsound and a bastardisation of Oxford's transport policy.

"In the run-up to Christmas you are going to have increasingly frustrated motorists trying to find a handful of free spaces.

"This is about the Tories wanting a flashy pro-car gimmick, but everyone will suffer if we encourage more cars back into the city centre including the motorists stuck in jams."

Traders claim Oxford is slipping behind rivals Swindon, Reading and Milton Keynes, mainly due to poor access to the city centre. The move to create free on-street parking has been welcomed by theatres, restaurants and shops.

City council leader Alex Hollingsworth said: "This exercise is costing a huge amount of money -- which is to be used for improving roads -- but the rich irony is that the county council is proposing to charge people living in the city to park outside their homes.

"The city will come to a grinding halt as people look for a free parking space."

But Mr Robertson said: "The pilot is to establish just what the effects will be.

"Initially there will be a bit of disruption, but we feel Oxford has been out of line with other cities."