Transport minster Tavish Scott said that the Cabinet agreed on the need to start planning now for a replacement Forth crossing in view of the recent findings of corrosion in the existing road bridge. There are no immediate safety concerns, said Scott, but there are potential long-term problems.

"Our most optimistic timeframe for replacing the crossing is 2014, if planning work starts now. But that planning may prove unnecessary, because at this point we don't have all the answers."