An extra £2m has been added to the cost of the Norwich Northern Distributor Road, as county councillors reaffirmed their desire for the controversial road's 'missing link' to one day be built.

The 19.5km road, as currently proposed, stretches from the A47 at Postwick to the A1067 Fakenham Road, but councillors yesterday made clear they have not abandoned their hope that it will one day stretch all the way around Norwich and link with the A47 to the west of the city.

Members of the county council's Labour/Liberal Democrat cabinet yesterday rejected a suggestion by officers that part of the road, between Fir Covert Road and the A1067, be single, rather than dual carriageway.

Officers had recommended that making that part of the road single carriageway would save £1.5m. That, they said, would help cover a £1.3m bill the council faces paying to Norwich International Airport - to pay for a new radar system.

The airport says its current radar system would get confused by the cars on the road, so a new one is needed to filter out the traffic.

But councillors, while acknowledging they will need to compensate the airport, said that should not come at the cost of the full dualling of the road.

They rejected the single carriageway idea, partly because they hope the road will one day continue past the A1067 and swoop round to join the southern bypass.

A 'complete' NDR was ruled out an earlier stage because the River Wensum is a Special Area of Conservation and it was concluded the cost of mitigating impacts would be too high.

But the Norfolk Conservatives' manifesto contained a pledge to 'fully complete the Norwich Northern Distributor Road to the western section of the A47', while the Liberal Democrat County Hall group recently called for a scoping report into the potential cost.

And at yesterday's cabinet meeting, Sue Whitaker, Labour councillor for Lakenham, said: 'Our aim has got to be a completely dualled road that links up with the southern bypass.' She said 'penny pinching' and making part of the road single carriageway would be 'folly', given the long term objective.

The cost of the road as currently planned is now £148.55m. In December last year, cabinet agreed to changes which tacked on a further £5m, while yesterday's decision regarding the radar adds £1.3m. A further cost is £750,000 for a roundabout at Fir Covert Road.

Richard Bearman, leader of the Green group, said the creeping cost of the road was a concern, as was the speed of the traffic which will use it.

He said: 'The quoted cost of the road of about £140m will be nowhere near what it ends up costing and that is a concern when this council is facing having to make significant savings.'

He said there would be 'considerable opposition' to any attempt to build over the Wensum valley to connect the road to the southern bypass.

County Hall officers have always said, even without joining the A47, the proposed road brings huge economic benefits and will bring relief on unsuitable and congested routes in and around Norwich.

A council spokesman said: 'Three of the main political parties have stated that the long term ambition should be to continue the NDR from the A1067 to the A47 west of Norwich, but this does not form part of the council's proposals because an environmentally acceptable and affordable way of crossing the Wensum Special Area of Conservation could not be found.'