AN EXTENDED 20mph zone has been approved for a busy Oxford road, even though police said it is unenforceable.

A further 250 metre stretch will be set up along Woodstock Road after Oxfordshire County Council's cabinet member for environment Councillor Yvonne Constance approved it yesterday.

A coloured central reservation will be created in the middle of the road, near Radcliffe Observatory Quarter.

But St Anne's College told the county council that it was worried it could cause confusion. Thames Valley Police said if the limit proves 'too low', it could 'result in the majority of drivers criminalising themselves'.