THE A14 Ellington-Fen Ditton improvements, including a new southern bypass for Huntingdon, could be shelved because the cost has doubled to £1billion, business leaders fear. When the preferred route for the scheme was revealed by the Highways Agency just last month, its cost was estimated at £639million. But the price tag still attached to it in Whitehall is the original estimate of £490million that was published on All Fools' Day 2003. At that time, the whole scheme was due for completion by 2010. Now it is unlikely to start before late that year, according to a regional spokesman for the agency. But John Bridge, chief executive of Cambridgeshire Chambers of Commerce, fears the £1billion cost re-evaluation could give a cash-strapped Government an excuse to ditch the scheme completely.