The Scottish Government approved the 28-mile Aberdeen Western Peripheral Route (AWPR) after a raft of local objections and a four-month public inquiry last year.

Finance Secretary John Swinney said the road would bring "substantial benefits" to the north-east of Scotland, but opponents have condemned the go-ahead.

The plans have provoked objections from a range of protest groups, including environmental campaigners and local residents unhappy about the proposed route.

Local campaign group Road Sense challenged the Netherley/Milltimber Brae route agreed by ministers and argued that it had been arrived at unfairly.

Friends of the Earth and the Scottish Green Party also criticised the plans.

Experts say the road, the costs of which are estimated to be between £300m and £400m, will ease traffic congestion in the city, with a 20% reduction expected on North Anderson Drive approaching the Haudagain roundabout.

The Government reporters who conducted the inquiry towards the end of last year had recommended that the road be approved.

Mr Swinney said: "The route will provide a much-needed bypass around Aberdeen, linking existing major roads and key locations such as the airport, park-and-ride sites and the major industrial estates around the city.

"The bypass will reduce congestion in the heart of the city as well as remove thousands of vehicles from the area’s rural roads, which are unsuitable for such high volumes of traffic."

Mr Swinney insisted he had considered the objections before making his decision.

He said: "Having given careful consideration to the issues and arguments, I agree with the reporters’ findings and reasoning, and with their recommendation to proceed with the bypass."

The announcement was welcomed by business and political figures.

Ian Armstrong, north-east manager for the Scottish Council for Development and Industry (SCDI), said: "The green light for the AWPR will boost economic

recovery and confidence. It will also unlock our economic future, securing our position as an attractive business location."

Labour’s Aberdeen Central MSP Lewis Macdonald backed the decision, but called for

funding of the road to be confirmed.

He said: "The Scottish Government needs to provide an assurance that the funding mechanism it has chosen for the new road is robust and will deliver value for money.

"We have waited long enough for this project and can’t afford further delays."

Liberal Democrat West Aberdeenshire and Kincardine MSP Mike Rumbles said the decision was a "welcome Christmas present" for locals and commuters.

He added: "I am, however, disappointed that they have waited until the Scottish Parliament went into recess before making this announcement. There are key questions outstanding about how the Scottish Government will pay for this project.

"It’s now absolutely crucial that the SNP keeps a close eye on the development of the AWPR."

The Government has previously said it hoped to build the road by 2012. Mr Swinney said yesterday that it hopes to seek contractors in 2010/11, but the remaining stages will have to be reviewed before a final timetable is issued.

Green Party co-leader Patrick Harvie led the criticism from the environmental lobby.

He said: "Alex Salmond’s administration has today issued a slap in the face to everyone who wants to see a successful, low-carbon Scotland, a Scotland which plays a responsible role internationally.

"Scottish ministers may have accepted Parliament’s tougher climate targets earlier this year but they are determined not to let those targets improve transport policy."

Dr Sam Gardner, climate change policy officer at WWF Scotland, said: "This traffic-

generating road project will increase Scotland’s carbon emissions at a time when we are all trying to do everything we can to reduce them.

"This decision quite simply flies in the face of Scotland’s ambition to be a low-carbon nation."

Friends of the Earth Scotland’s chief executive Duncan McLaren said of the approval: "This is a mistaken and poorly judged decision that will make it more difficult to tackle climate change and reduce greenhouse gas emissions in Scotland. "