Sections of the M1 between Leics and South Yorkshire will be extended to five lanes in a �1.9bn project.

But the "No Widening of the M1" group said the move would generate more traffic and increase pollution levels.

The Highways Agency is to expand three-lane sections into four with an additional crawler lane on hills for lorries to use.

'Journey reliability'

Sam Brown, of the opposition group, said: "You can't build your way out of congestion.

"It's been proved by the government's own transport white papers that increasing the capacity of roads does not reduce congestion.

"In fact it increases the amount of traffic - which has been proved recently by a study on the Newbury bypass where traffic has increased by 50% in the first five years of it being built."

A public consultation exercise is to begin in the spring on the widening of the motorway by one lane between Junction 21 at Leicester and Junction 30 at Chesterfield.

Tony Turton, of the Highways Agency, said: "Journey times are predicted to rise on this particular section between 50% and 60% by 2030.

"This project will create additional capacity to allow that traffic to flow efficiently.

"The main aim is really to improve journey time reliability, improve roads user safety and reduce driver stress."

Construction work is scheduled to begin in 2007.