Work involved in the �134m dualling of the last single stretch of the A11 will begin on Monday, following a decison to bring part of the project forward from next year.

Preliminary work on the long-awaited dualling between Thetford and Barton Mills is set to begin with an access road at the Elveden Estate for heavy farm vehicles.

Upgrading the access has been accelerated to ensure main construction work to widen the last nine-mile stretch of the A11 starts on schedule in 2012/2013.

Prime minister David Cameron confirmed last month that the scheme would begin in the next financial year and the latest news was welcomed by campaigners who have fought for decades for the road's completion – due in 2014/2015.

South West Norfolk MP Elizabeth Truss who, along with West Suffolk MP Matthew Hancock and others, made sure the A11 remained at the top of the political agenda in the lead-up the government spending review last year, said she was 'so excited'.

'I've been told that initial work is going to be started, which has been brought forward by a year,' she said. 'It isn't construction work but it's going to be on-site preparation.

'If the work had been left longer there would have been no contingency in the schedule for bad weather or anything like that. I think this should give people confidence it will now be delivered on time.

'I think it's terrific news and the sooner we get that road fully functional the better. We need new businesses, and growth to our current businesses in Thetford and further afield, and this news is really fantastic. I think the importance of a physical presence is huge because businesses will be able to start making plans knowing the road is going to happen.'

Following a public inquiry last year, chancellor George Osborne confirmed in last October's comprehensive spending review that the government would press ahead with the A11 and 24 hours later roads minister Mike Penning confirmed funding was in place.

MP for Great Yarmouth Brandon Lewis said: 'The difference is now work is starting, This is really positive because people can see the government is doing what it said it would. The government knows the quicker this gets going the quicker the returns and the quicker we get the economy going.'

While Highways Agency staff have been carrying out initial studies at the single stretch of nine-mile carriagway for the past few weeks, this will be the first time work will actually begin.

The dualling is a key improvement to transport links between Norfolk and the rest of the country. Research by the then East of England Development Agency two years ago showed the scheme would save �690m in lost time when completed.

Mike Brown, spokesman for Gateway A11 East and deputy chairman of the Thetford Business Forum, said now was the time to make the most of any opportunities to arise from dualling.

'It doesn't just mean a lot for Thetford, it means a lot for the whole community,' he said. 'Hopefully we'll have a cohesive strategy for making best use of the opportunity. 'Personally I think the businesses have been looking forward to this since the decision was made and have been planning towards it. The key now is for collaboration between the public and private sector to make best use of the opportunity.'

Graham Plant, cabinet member for planning and transportation at Norfolk County Council, said: 'This starting on site will begin to make the dualling a reality for Norfolk people who have wished for this for decades.

'Whether a start on preparatory work brings forward the completion date remains to be seen, but we will certainly be pressing the Highways Agency to complete the job as quickly as possible on behalf of Norfolk residents.'