The History of the Dartford Crossing
For over 50 years, the Dartford Crossing (A282) has provided the only road crossing of the Thames east of London. The opening of the first crossing in 1963, the west tunnel, predates the remainder of the London Orbital's construction in 1969 by six years. Today the A282 remains the only section of the London Orbital not built to motorway standard.
in 1990 the Secretary of State for Transport announced plans to widen the whole of the London Orbital, now known as the M25, to four lanes. By 1993 the motorway, which was designed for a maximum of 88,000 vehicles per day, was carrying 200,000 vehicles per day. 15% of UK motorway traffic volume was on the M25.