The new Forth Road Bridge could be built for up to GBP700 million less than original estimated.  The Scottish Government unveiled the consortium that is set to spearhead the biggest building project in Scotland in a generation after it was chosen as the preferred bidder for the scheme by ministers yesterday.  But the announcement was branded "blatant electioneering" by opposition parties and campaigners, who said the decision ties the hands of the incoming government after the May election.  Ministers say the condition of the existing bridge, linking Edinburgh and Fife, is deteriorating. The new Forth road bridge is due for completion by 2016.  The Forth Crossing Bridge Constructors (FCBC), which has been chosen as the preferred bidder, comprises Scottish firm Morrison, as well as Dragados, Hochtief and american Bridge International. It beat competition from Forthspan after an 18-month tender process.  FCBC's successful bid for the design and build contract is GBP790m, representing a saving on the initial estimated cost of GBP1.2 billion.  a spokeswoman for the winning consortium said: "This project has been on the drawing board for many years and we are delighted to be making a positive contribution in bringing it to reality."  The cost of the project has fallen to a figure of between GBP1.47bn and GBP1.62bn, significantly down on the original estimate of between GBP1.7bn and GBP2.3bn.  Government transport agency Transport Scotland said the cost had gone down because of a reduction in price of the principal contract and the removal of other costs due to UK Treasury changes.  Finance Secretary John Swinney said: "It is a testament to the robust competition we put in place that it has delivered a bid representing a significant saving for Scotland's capital budget.  "The Forth Replacement Crossing project will be essential in protecting and promoting Scotland's sustainable economic growth, safeguarding a vital link in the country's transport infrastructure, protecting thousands of jobs and securing more than a billion pounds in economic revenue.  "The successful FCBC consortium includes world-class bridge building and civil engineering firms with strong records of successfully delivering similar projects throughout the world."  Scottish Labour transport spokesman Charlie Gordon said the party welcomed the progress being made on the bridge project.  But he added: "You have to question the motives of the SNP government in making this announcement so close to the election. as alex Salmond heads towards the exit door it is becoming clear that he is abusing his position for the purposes of blatant electioneering."  It is now expected that the contract itself will be formally signed in the "purdah" period next month after parliament has dissolved and the election campaign is under way.  Green MSPs yesterday wrote to Sir Peter Housden, Permanent Secretary to the Scottish Government, challenging his decision to allow SNP ministers to sign contracts. Co-leader Patrick Harvie said constitutional convention prevents ministers from taking decisions like this during this period.  Mr Harvie said: "The routine and uncontroversial business of government has to continue, but this decision is anything but - it's an extravagant, unnecessary and unpopular project being awarded by the SNP as an election stunt.  "Opposition to this timing is growing, with MSPs from Labour and the Lib Dems as well as Greens all signing a motion urging a prudent delay until the new parliament and government are chosen."  Liberal Democrat transport spokeswoman alison McInnes said: "It is unprecedented to award a contract of this scale after parliament has dissolved.  "The SNP are playing politics by announcing the consortium to build the bridge the day before parliament dissolves.  "This is almost certainly the largest single contract in the Scottish Parliament's history. While we want work on the bridge to begin, the new, incoming government should have had the chance to scrutinise the detail of the contracts."  Local campaign group the ForthRight alliance called on Sir Peter to re-consider his decision to allow the contract to be signed next month.  Chairman Lawrence Marshall said: "No-one can pre-judge the outcome of the May election. No-one should negate the ability of any party to put this important policy and financial issue