Campaigners were last night drawing up battlelines after deputy Prime Minister John Prescott ordered a public inquiry into proposals for a second Tyne Tunnel.

The decision to place the New Tyne Crossing under the spotlight was welcomed by environmentalists as a "victory for common sense and democracy".

South Tyneside Friends of the Earth campaigner Bryan Atkinson said: "The arguments for building the Tyne tunnel are riddled with flaws and inaccuracies.

"These will be exposed during the public inquiry. The battle doesn't stop here."

The existing tunnel carries both northbound and southbound traffic and was designed for a capacity of 24,000 vehicles a day. It now carries 36,000 vehicles a day, resulting in congestion and delays_ and is forecast to hit 52,000 by 2021.

The new proposed tunnel, which would cross between East Howdon and Jarrow near the existing tunnel, will be built under the government's Private Finance Initiative at a cost of £139m.

It will be used only by southbound traffic on the A19 while the present tunnel would be converted to take only northbound traffic.

The North East Chamber of Trade has argued the new tunnel, which will increase capacity to 76,000 vehicles a day, is essential for future economic growth and job creation.

But FoE say there will be huge increases in traffic levels, not just on the A19 river crossing but also on adjoining roads, when public transport alternatives were not studied.

Members have also voiced fears about thousands of tonnes of potentially contaminated material to be dredged from the river.

Tyne and Wear Passenger Transport Authority vice chairman Councillor Muriel Green said: "The PTA welcomes the announcement by the deputy prime minister.

"We have always made it clear that public inquiry would most likely be held into our proposal for the New Tyne Crossing.

"We believe this is the best place for all parties to air their views and the fairest way of considering the New Tyne Crossing."

No date for the inquiry has been announced, but is expected to be held late winter early spring.

Meanwhile, national conservation advisors to Government, English Nature announced last night it had withdrawn concerns it had initially raised with developers. .