Widening the A12 could cost at least £10 million-a-mile, a top civil engineer warned today.

This would equate to a bill of more than £1,400 for every home in Essex.

Francis Connolly, a recently-retired senior partner at global firm Peter Brett Associates, claimed other services could suffer if Essex County Council decides to use council tax cash to fund improvements.

He said the need to keep the major trunk route open while works were carried out could double the size of the eventual bill.

Council leader Lord Hanningfield has said he will consider borrowing money to sort out congestion woes on the road, even though it is the responsibility of the Highways Agency, as he is fed up of waiting for funds to be released by the treasury.

He believes widening from a dual to a three-lane carriageway for the whole length of the A12 in Essex will prove to be the long-term solution.

Mr Connolly, who oversaw major road schemes across the country over 33 years, claimed it could "easily" cost £10 million a mile - or £1,900 a foot - to expand all the two-lane sections.

That tallies with an estimate worked out by the council several years ago of £800 million, equating to £1,468 for every home in Essex.

It calls into question whether the Essex stretch will ever be completely widened to three lanes for nearly 50 miles from the M25 to the Suffolk border, as the annual Government budget for road schemes across the East of England is just £75 million.

"Widening existing roads can be frighteningly expensive," said Mr Connolly.

The council has appointed Sir David Rowlands to hold a public inquiry into the state of the A12.

The first of three hearings will take place from 10am to 5pm at County Hall tomorrow.

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