The long-running campaign for a major bypass in east Suffolk has been boosted by welcome reports of a substantial financial offer.

EDF Energy is said to have agreed possible new funding for the four villages A12 bypass – or Suffolk Energy Gateway – as part of its Sizewell C power plant proposals.

People have been calling for a bypass around Marlesford, Little Glemham, Stratford St Andrew and Farnham for at least 20 years, claiming the traffic is too much for small villages.

Campaigners say Sizewell C’s development, bringing thousands of extra lorries, would make a bad situation worse and demanded EDF help fund the bypass.

EDF’s latest consultation recognised construction related traffic required A12 improvement. However its offer stopped at a two villages bypass around Stratford and Farnham, which it claimed would be appropriate mitigation.

Now, however, EDF is reported to have shown greater support for the full bypass proposal.

Lord Marlesford, who has been involved with the campaign since its beginning, met with EDF this month when he claims the offer was made. He says EDF indicated it would contribute equivalent funding for the two villages bypass towards the full scheme. “This is a big step forward and is most welcome,” he said.

With EDF’s contribution, campaigners believe their chances of securing the remainder are vastly improved, particularly with the recent Government support.

The Sizewell C Joint Local Authorities Group (JLAG) was given £1million by the Department for Transport last year to support the Energy Gateway project.

Lord Marlesford said he was encouraged by this – but warned political changes may undo the good work. He said JLAG chairman Guy McGregor had been a driving force behind the project but may be replaced in a reshuffle expected tomorrow. “Guy McGregor has really pushed things forward and without him I fear we may lose momentum,” Lord Marlesford said.

Mr McGregor has been elected chairman of the Conservative group at Suffolk County Council. However he said he would happily continue with JLAG and welcomed the financial news.

An EDF spokesman said: “Over the years we have had regular discussions with the Suffolk local authorities about their ambitions for a four villages bypass and will continue to engage with them while they continue to work on their proposals.”