An agreement to borrow £40m towards Norwich's controversial Northern Distributor Road could leave councils facing a 'toxic debt', angry opponents warned today.

Norwich City Council last night agreed a tax on house building should be used to repay the loan and its interest over 25 years - a loan needed to build part of the £178.5m road.

The 12.5 mile road is due to stretch from the A47 at Postwick to the A1067, but the cost of the section between the A140 at Norwich International Airport to the Fakenham Road has not been covered by the government.

Norwich City Council agreed to join forces with the county council, Broadland District Council and South Norfolk Council to borrow up to £40m for that stretch of the road.

The loan and the interest repayments, which could be as much as £15m over a quarter of a decade, will be paid back using the community infrastructure levy – a tax on developers who build new housing.

But Andrew Boswell, leader of the Green group at Norwich City Council, and a long-standing objector to the NDR warned the use of the community infrastructure levy for the road would stop other community projects happening.

He said: 'In terms of what could be achieved in the city, I see that as a toxic debt, preventing us from doing good things in the city. '

He said a more pragmatic approach would be to stop the road at the A140, rather than continuing to the A1067.

Alan Waters, Labour leader of Norwich City Council, said spin-offs from the road would see community improvements, including to public transport.

He said only about 25pc of the levy would be used to cover the borrowing and its interest. He said other projects, such as the Long Stratton bypass, were earmarked to benefit from that development tax.

And he added the council's budget would not be affected by the agreement, with the county council liable to cover any overspend.

He said: 'It's frankly vital to the future of the city and its residents. It has many benefits.'

Before the meeting, protestors, including Green councillors and members, Friends of the Earth and Greenpeace, campaigned on City Hall's steps.

Speaking afterwards, Jennifer Parkhouse, from Friends of The Earth, said she was 'hugely disappointed', while Richard Hawker, from Hockering Parish Council, said: 'It seems the majority of our elected councillors seem determined to have this road in spite of both common sense and the will of the people.'

A £30m escalation in the road's cost is already having to be plugged by the government, Norfolk County Council and the New Anglia Local Enterprise Partnership.

Initial work on the road is due to start next month, with full blown construction commencing next February or March.

Supporters of the road say it will be a shot in the arm for the economy and reduce rat-running. But critics say it will increase traffic and pollution, while causing swathes of countryside to be concreted over.

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