Communities are uniting in the demands they are to make as part of the development of a nuclear power plant in east Suffolk.

Representatives from 50 town and parish councils met the Joint Local Authority Group (JLAG) to agree a range of measures they will call on EDF Energy to deliver in phase two of its Sizewell C consultation.

The meeting agreed the need for the whole community – Suffolk County Council (SCC), Suffolk Coastal District Council (SCDC) and parish councils – “to work rapidly together” to press EDF to agree its terms.

Long-held aspirations for a four villages A12 bypass are included in the demands along with assurances for Yoxford, Middleton and Theberton to be protected from the “predicted substantial increase in traffic on the B1122”.

JLAG, which is formed from SCC and SCDC members, also agreed to push EDF to present an “early timetable” for its future plans.

More than two years has passed since phase one of the Sizewell consultation went out and the date for phase two has been repeatedly delayed. When it arrives, JLAG is also urging for there to be at least 12 weeks’ community consultation – rather than the eight proposed – so that people have sufficient time to consider what is an “extremely complex” project.

JLAG chairman Andy Smith said the “resounding view” of the meeting was that EDF needed to provide more detailed information for the consultation, which he urged “as many people as possible” to take part in. “I would urge all local communities to ready themselves,” he added. “We don’t yet know when it will begin but it is currently not scheduled to run for long, so readiness to respond will be essential.”

Debbi Tayler, spokesman for the Four Villages Bypass group, said she welcomed the outcome, which was “what we have been pushing for all along”.

She said the need for a bypass around Stratford St Andrew, Farnham, Marlesford and Little Glemham was more apparent than ever, highlighting the “astonishing” traffic that built up during recent road works, which she says will only worsen during Sizewell’s construction.

Tony Middleditch, a Yoxford councillor, who has been campaigning for EDF to abandon its plans for construction traffic to use the B1122 in favour of a new road built further south known as the “D2” route, also welcomed the progress made.

“I think they’ve realised there’s a problem that the D2 route would solve and at least now they are putting pressure on EDF,” he said.

Leonora van Gils, a Darsham resident who has highlighted the problems faced by homeowners while EDF’s plans are dragged out, also called for more clarity.

“Why are they taking so long?” she asked. “Do they think it is fair to have people not knowing for all this time?”

EDF Energy said it was “committed to a full and robust consultation” and would be providing more information about the project in the next stage, the timing of which was linked to the final decision at Hinkley Point, its other nuclear power project in Somerset.

In the meantime, people were invited to raise questions at the Sizewell C information office in Leiston High Street.