A new bridge will be built across the Forth in Scotland's biggest construction project for a generation, finance minister John Swinney told MSPs today.
The crossing has an estimated cost of between 3.25 billion and 4.22 billion
And Mr Swinney said the bridge – which could open in about nine years time – would become an iconic structure.
A new crossing is required because cables on the existing Forth Road Bridge are corroded, and there is a possibility it may have to close to lorries by 2013 and to all traffic by 2019.
Today Mr Swinney told the Scottish Parliament that action was required to be taken now.
'Doing nothing is not an option,' he said.
And he revealed that after considering all the different options – including two different types of tunnels and two different kinds of bridges – the Scottish Government had opted for a cable stayed bridge.
This will have three pylons or towers, with cables running from these supporting the decks of the new bridge.
As well as being the cheapest of the options the government considered, it is also one of the quickest to build, with construction estimated to take some five and a half years.
Mr Swinney told MSPs: 'The new Forth crossing is a hugely ambitious project.
'It will be the largest construction project in a generation in Scotland. It will be an iconic structure.'
The bridge will run from the northern shore, just west of the existing road bridge, to a point west of South Queensferry.
And Mr Swinney said it would maintain a 'fundamental link' across the River Forth while providing better connections to the transport network.
He added: 'The Forth Rail Bridge created an image of global significance when it was constructed in the 19th century.
'In the 21st century our vision of a new crossing of equal stature and significance is the government's promise today.'