START (GR389596) on St Neots Road west of Madingley RAB about 626yds west of RAB at a point 6yds west of ‘Comberton 2’ sign and 95yds west of road leading to Comberton. Proceed eastwards to Madingley RAB where take 1st exit onto A428 westbound, past Hardwick and Cambourne flyover junctions to: TURN (6.56m) at Caxton Gibbet RAB (junction with A1198). Retrace A428 eastbound and about 1 mile past Hardwick flyover bear left onto A1303 sliproad, signed Cambridge, follow over A428 to: TURN (12.86m) at Madingley RAB taking 4th exit to rejoin A428 and retrace westbound to: TURN (19.13m) at Caxton Gibbet RAB. Retrace A428 eastbound and again bear left onto A1303 sliproad, signed Cambridge, to: FINISH on sliproad 15yds past ‘Bend’ sign.