hit the tunnel's inner lining. New tunnel Due to the increase in motor traffic in the early 20th century, the capacity of the original tunnel was soon perceived as inadequate. In 1930, John Mills, MP for Dartford, remarked that HGVs delivering from Essex to Kent could not practically use any crossing of the Thames downstream of the tunnel. The LCC obtained an act to construct a new tunnel in 1938, but work did not start due to the outbreak of World War II. Construction eventually started in 1958 with preliminary work on the northern approach road. By this time, traffic had become progressively worse. In 1960, Richard Marsh, MP for Greenwich complained that vehicles could spend 30 to 45 minutes stuck in tunnel traffic. The new eastern tunnel, in diameter, was accepted into the roads programme in March 1959, and construction started in March 1960. It was opened on 2 August 1967 by Desmond Plummer, Leader of the Greater London Council (GLC). It is wider than the western tunnel, carries two lanes of traffic and is usable by vehicles up to in height. During construction, transport minister Ernest Marples clarified that unlike the Dartford Tunnel, also then under construction, tolls would not be imposed as the tunnel was already an established route. At the time of opening, the strip lighting in the tunnel was commended as "a big improvement" on the standard provided in the original tunnel. In contrast with the Victorian northbound tunnel, the eastern tunnel had no sharp bends, and emergency telephones were provided. Its distinctive ventilation towers were designed in 1964 by GLC architect Terry Farrell. Immediately after opening, the old tunnel was closed for refurbishment. It re-opened on 4 April 1969 with a new electronic system to detect overheight vehicles. In the late 1960s, proposals were made to connect the tunnel with a free-flow, grade-separated motorway system as part of the London Ringways project. Aside from the construction of the A102(M) Blackwall Tunnel approach roads, opened in 1973, these plans were abandoned. The entrance gateway to the northbound tunnel was Grade II listed in 1973, while the ventilation towers were listed in 2000. In April 1986, the tunnel became part of the UK trunk road network. It was detrunked and control handed to TfL in September 1999. Provisional IRA bombing On 18 January 1979, an anonymous caller to the Press Association informed them that the Provisional