The west flank (the Charing Cross and Kingston Bridge sections) was planned to run from the St George's Cross interchange, sweeping beneath Charing Cross and through Anderston before rising to cross the River Clyde and run to an interchange at Tradeston. The river crossing, whose feasibility had been considered even before the proposal of the ring road, was completed in June 1970 and opened by Queen Elizabeth, the Queen Mother. The Charing Cross section completing the link to St George's Cross was made in February 1972, marking the end of the originally contracted work. The North and West Flanks form 2.5 miles of motorway, built at a cost of around £27 million.