Westmorland and Lonsdale MP Tim Collins is pushing for work to start on a long-awaited by-pass on the A590.
The £22 million, 3.8 kilometre by-pass at High and Low Newton, has been touted as a scheme that would save many lives on the notoriously dangerous road.
Eighty people have died on the road in the past 19 years.
Mr Collins, who is also shadow secretary of state for education, is urging ministers to commit to a start date for the project.
The scheme was added to the National Trunk Road Programme a year ago but work has not yet begun.
Mr Collins said: "Ministers should quit stalling and instruct their officials to get this desperately needed by-pass built.
"There really can be no excuses for delay. The project already has planning permission. Indeed, in 1997 the plans were approved and the bulldozers were ready to roll before John Prescott blocked the project."
He added: "Now this Government has itself accepted that the project is a very high priority. The Treasury is taking billions of pounds in extra taxes each year and a tiny proportion of all that could pay for this road to be built.
"I urge ministers to put their money where their mouths are and set a start date."
Government spokesman Clive Naish said: "There isn't a delay. It's a misnomer to say there's a delay.
"The Government carried out a spending review earlier in the year and announced extra money for the departments.
"What the departments are now doing is deciding where that money will be allocated.
"High and Low Newton was put into the targeted budget of improvements last year and work has been progressing in preparing it and we are just awaiting the decision from ministers as to when work starts."
A decision is expected this autumn but Mr Naish could be no more specific than that.
Backers of the bypass have highlighted a Cumbria County Council economic assessment released this year which said the need for better roads was "greater than ever" in the light of major redundancies over the past 18 months at BAE Systems in Barrow, and because of regeneration work in the peninsula.
The Highways Agency has revealed that it only has £30,000 to provide improvements to the road in this year's budget, which equates to around £1,000 per mile.
The £30,000 budget does not extend to the costs of maintenance or the bypass.
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