Advisers on both sides of the border have begun jostling for position after the Scottish Executive last week announced it was to press ahead with controversial plans for a new £1bn crossing over the Firth of Forth.

The project promises to be one of the biggest ever in the Scottish market and a raft of major firms have put themselves in the frame to win mandates when details of the scheme are finalised this summer.

It is understood Dundas & Wilson is in prime position to score a major role on the back of its existing relationship with the Forth Estuary Transport Authority (FETA), the body responsible for overseeing the current bridge and the surrounding area.

Dundas' 'big four' Scots rivals McGrigors, Shepherd & Wedderburn and Maclay Murray & Spens are also likely to put their names in the hat alongside a number of UK national firms.

A competitive tender for this kind of high-profile infrastructure project is also likely to attract interest from the City.

The Scottish Executive currently operates an 11-strong legal panel that includes UK giants Pinsent Masons, CMS Cameron McKenna, DLA Piper and the big four Scots firms, as well as regional outfits Burness, Morton Fraser, Harper Macleod and Brodies.

A spokesperson for the Scottish cabinet said: "This has the potential to be the biggest project in Scotland since devolution."

One Dundas partner said: "A lot of law firms on both sides of the border are already looking at this as a project with the potential to crack the market wide open, and they have invested a lot of time and cash in getting up to speed."

The plans, which were unveiled last week by Scots transport minister Tavish Scott, centre on a new crossing, either a tunnel or a bridge, to replace the existing Forth Road Bridge, which is suffering from severe corrosion.

Three different plans are available to Government ministers and a final decision is expected this summer.