A nuclear watchdog group has sent a mixed message to officials drawing up a new emergency plan for the community living near the Sizewell power station site.

Under draft proposals put forward on behalf of the Suffolk Resilience Forum, comprising emergency services and local authorities, the radius of the emergency zone will be increased from 2.4 to four kilometres – in line with new international guidelines.

If agreed, the new radius will ensure that 5,600 people, including the entire population of Leiston, will be given advance details of what they should do in the event of a major release of radioactivity from the Sizewell site.

The Sizewell Stakeholder Group (SSG), a forum for improving communication between the local community, the nuclear operators and safety regulators, has previously voted in favour of an emergency zone of up to 20km in view of the evacuation that took place after the Fukushima disaster in Japan.

However, the SSG, which is being consulted over proposed changes to the existing off-site emergency plan, decided to let members select from a variety of options rather than vote on the official proposal.

The result was that six members voted to back the 4km plan, with a similar number voting in favour of a 20km zone.

There were two votes in support of the 2.4km status quo, while Nigel Smith, who represents the villages of Middleton, Theberton and Eastbridge, plumped for a 10km radius.

He said: 'Under the current proposals, there are going to be 5,000 people trying to get out of Leiston and another 500 trying to get in to pick up families. It is going to be chaotic.'

Whatever the size of zone agreed, the public needed an assurance that emergency services could get people out of the area safely, Mr Smith said.

Joan Girling, a co-opted SSG member and chairman of Communities Against Nuclear Expansion, said an extension of the current emergency zone would in no way amount to a slur on the site operators.

'The plan has just got to be in the best interests of the local community,' she said. 'It needs to give a sense of confidence that an evacuation can take place.'

The public consultation over the draft new emergency plan ends on April 8.