Plans to build a new bridge across the Mersey should be scrapped, according to a campaigner on the first day of a public inquiry.

Lillian Burns argued that a toll should be imposed instead on the existing crossing at Runcorn with the money used to improve public transport.

Inspector Alan Gray will scrutinise the £400m "Mersey Gateway" project – set to create 4,640 new jobs – at the inquiry.

The hearing, expected to last for six weeks, is being held at Stobart Stadium in Widnes.

Around 70 people attended the opening on Tuesday with both sides lined up to present boxes of evidence.

Mrs Burns was the first objector to speak for The Alliance, representing Friends of the Earth, the Campaign to Protect Rural England and the NW Transport Activist Roundtable.

She said: “It would appear that all the structural works could be more than £1billion, not the half billion usually quoted.

“The new bridge is due to open in 2015 and the operator only has 27 years, until 2042, to recover costs and make a profit and then hand it back to Halton Council.”

She claims it will not be commercially viable.

“From evidence of the M6 toll, HGVs won’t use it unless they have to."

Instead, she proposed “a very modest toll” should be levied on the existing bridge and the money ploughed into public transport, instead of investing in a second crossing.

Under the project, the new bridge and existing Silver Jubilee Bridge will be tolled.

The toll levels have yet to be decided, but are expected to be in line with that of the Mersey Tunnels.

In July of last year, campaigners warned the new bridge will impose huge hardship on drivers in Cheshire, Liverpool, Merseyside and Lancashire.

They said that forecast toll levels meant a daily commuter using the new bridge will pay a staggering £118,000 in tolls during a lifetime.

John McGoldrick of The National Alliance Against Tolls (NAAT) warned that the Mersey Gateway would be “a disaster” for drivers and businesses in Chester, South Liverpool, St Helens, Wigan, Knowsley, mid-Cheshire and West Lancashire.