OXFORD could become the first city in the UK to introduce a near-blanket 20mph speed limit.

Councillors are to consider extending the 20mph speed limit to most roads in Oxford. Even the main arterial routes into Oxford, such as the Banbury, Botley, Iffley and Abingdon roads, will be looked at.

Campaigners have had limited success in getting 20mph limits in parts of Cowley Road, Summertown, Jericho and some residential areas. But Oxfordshire County Council is moving towards the idea of a citywide limit in one go, removing all uncertainty for road users.

Ian Hudspeth, county council cabinet member for transport, said that while Portsmouth has been slowly turning itself into a 20mph city, Oxford could become the first to go for "a big bang approach".

He said a scheme could be in place by end of the year or next spring, depending on the outcome of a major consultation planned to assess the level of public backing for such a radical approach.

The introduction of 20mph limits in Cowley Road has seen a 35 per cent reduction in accidents. This has encouraged campaigners to call for the whole city within the ring road included, along with areas such as Blackbird Leys and Littlemore.

A report to go to county councillors next month will set out options and assess how far the 20mph limit can be extended.

Mr Hudspeth said: "We will have to look at some roads and decide whether it is really practical for people to go at 20mph all the time.

"Then we will have to decide whether to implement it zone by zone or go for a big bang approach, which I would favour. It would be easier for everyone to understand with everything changing on a particular day."

While evidence showed that 20mph limits would reduce accidents in busy shopping areas such as Summertown, he believed introducing limits along main routes into the city would prove controversial.

But road safety campaigners are hoping to use the consultation to marshal public support for making all Oxford a 20mph zone to transform the quality of life in the city.

Paul Cullen, of the Life Begins at 20 group, said: "I think it is important that 20mph limits are introduced on bus routes. These are roads that see maximum pedestrian and cycling activity, as well as being the main school routes."

He said surveys showed 20 mph limits did not affect journey times in cities. "All we presently have is motorists accelerating up to 30mph and then having to slow down at traffic lights. And it should be remembered that all the arterial routes in Oxford are residential streets as well.

"As well as reducing accidents, it would bring social benefits.

"The worst thing would be to send out a mixed message, where drivers simply don't know if they are in a 20mph zone or not."

County Hall puts the cost of introducing a citywide 20mph speed limit at £300,000.

John Disley, road safety manager at County Hall, said the county had to be mindful of Government advice that 20mph limits should only be introduced where average speeds were already low, with an average below 24mph.

And he warned: "Most existing speed camera systems are not able to enforce 20mph limits. There is now a need for us to look at the whole question of enforcement."

The proposal was given the backing of Oxford City Council's executive this week.