IRA had planted a bomb in the tunnel that was scheduled to detonate at midnight. While the Metropolitan Police were searching the tunnel, the bomb detonated at 12:40 a.m., causing an explosion in a gas holder near the southern exit. This resulted in a fire on another gas holder approximately an hour later. No injuries were reported. Speaking in the House of Commons, Home Secretary Merlyn Rees hoped "the House will join me in condemning these attacks and will support the Government in their determination not to be swayed by such methods". A Belfast man was jailed in May 1983 for his role in the bombing, and was eventually released at the end of his sentence some 17½ years later, still professing pride in his IRA participation. Nearest alternative crossings TfL state that one of the major issues with the Blackwall Tunnels is the lack of resilience in the event of an incident—as the nearest alternative road crossings are the Rotherhithe Tunnel to the west, Tower Bridge to the west, and the Dartford Crossing to the east. The Woolwich Free Ferry is to the east, but is closed overnight, often reduced to one boat in operation, or completely closed at weekends. Variable message signs (VMS) near the tunnel inform drivers if the ferry is available. When open, queuing for the ferry causes significant congestion around Woolwich town centre. Underground railway links include the Jubilee line from North Greenwich (TfL) to Canning Town on the east and Canary Wharf on the west. The Docklands Light Railway also passes under the Thames between Island Gardens at the southern end of the Isle of Dogs and Cutty Sark in the centre of Greenwich. Horse-drawn traffic was partially banned from the tunnel during peak hours in July 1939 and completely banned in August 1947. Pedestrians have been banned from using the Blackwall Tunnels since May 1969. The London Buses route 108 (Stratford–Lewisham) runs through the tunnels and there are bus priority gates at both entrances to allow buses to avoid traffic congestion. On occasion in the past, the bus service has been escorted through the tunnel when it has been closed. Traffic management The northbound Blackwall Tunnel is a traffic bottleneck with tailbacks. A TfL study in 2009 revealed that the approach to the northbound tunnel took around 19 minutes in rush hour traffic, or a delay of approximately 11 minutes per kilometre. To