WIDENING the M42 would damage the Meriden Gap and cost hundreds of millions, a conservation charity has claimed.
The Campaign to Protect Rural England calculated that construction work, between junctions 3a and 7, could cost £300m.
Members were reacting after the possibility of widening the motorway was brought up by the Birmingham and Solihull Local Enterprise Partnership.
The organisation wants to improve the traffic flow along the M42 corridor to boost growth in the region.
But Jerry Birkbeck, chairman of West Midlands CPRE, said that the idea had not been thought through.
“It’s a knee-jerk reaction,” he said. “They don’t seem to have realised the full impact or the cost involved.
“A lot of land will be taken to add an extra lane on both carriageways but of course the development would involve much more than that.
“Bridges would need to be extended and work carried out on junctions - it would have a knock-on effect.”
Solihull Council had talked about congestion problems in a recent issue of the magazine Local Transport Today.
The local authority claims that the limited capacity of the transport network restricted growth in the area.
But green campaigners have argued that improving rail, bus and tram links was a much better strategy in the long term.