BBC Essex Kent Live Thurrock Gazette Highways England It is hard to imagine a time before the M25 sliced though Dartford and the bridge linked it up. Before the QE2 Bridge construction there was originally just the tunnels linking Kent and Essex. Work on the first tunnel began in 1936 and was paused by the Second World War. It resumed in the 1950s opening in 1963 allowing for single lane traffic in both directions. The second tunnel opened in 1980.