There is little doubt that the announcement by Thames Valley Police that they will be finally enforcing the 20mph limits in Oxford will lead to more requests for similar limits from people in other parts of the county.

Oxfordshire County Council has turned down requests for the lower limits in the past on the basis that if the police were unwilling to enforce them, then there was no point in going to the considerable expense of introducing them.

The police view up to now has been that the 20mph speed restriction should be largely self-enforcing by use of signage and road engineering. Now senior police officers say that those caught ‘straying just over the 20mph limit’ will be dealt with by roadside cautions and advice, with more serious speeding offences being prosecuted. With the alteration in the police stance, it is inevitable that more communities will be bidding for a reduction in limits.

There is little doubt that 20mph is a perfectly sensible speed limit for traffic to travel in narrow, residential areas, where pedestrians, children and cyclists have to vie with cars and lorries — indeed in some parts of Oxford it would be a challenge to maintain that heady speed.

But we are less convinced by the blanket imposition of 20mph limits on roads where a higher limit would be more realistic.

At least we now have some hope of judging the real effectiveness of this costly road safety idea.