“The Thames at War” (2020) contains a detailed account of the bomb damage and subsequent repairs to the northern section of the Greenwich Tunnel. We reprint an extract from this excellent publication by kind permission of the author Gustav Milne and publishers Pen and Sword. The book is commended to anyone interested in war damage to the Thames embankment and its immediate surrounds. There is a whole chapter on the Blitz and the Greenwich waterfront.
(Pages 95-97 from “The Thames at War” follow)
Greenwich Foot Tunnel
Although not directly the responsibility of the Thames-Flood team, damage to tunnels and bridges also had to be repaired by LCC’s Chief Engineer. One such example is given here, to provide an engineering perspective on the T-F’s programme. At 5.30pm on 7 September 1940 an HE bomb exploded on the foreshore 12 yards from the river wall, directly over the line of the tunnel. The tile and concrete lining of the tunnel collapsed over a length of 30ft (10m). The Poplar shaft also took a direct hit from an oil-incendiary bomb, destroying the electrics for the lift mechanism, and the Greenwich shaft was hit by another incendiary on the following Sunday.
On 8 September 1940, as the tunnel began filling with water, emergency measures were taken to prevent further collapse: LCC’s Chief Engineer visited the site personally to assess the dire situation and initially assessed the damage at £30,000. By 14 September, the entire tunnel was flooded, as were both shafts; it was thought it might take up to three months to pump it all out. However, once the pumps had been installed, it actually took only ten days of continuous pumping to clear sufficient water to provide safe access and start clearing the debris. Since the floor of the tunnel slopes downwards as it approaches the middle of the river, it proved possible to work on the higher end of the tunnel, close to the Poplar shaft, even if the longer, lower section of the tunnel remained partially under water. The initial emergency repairs comprised temporary shuttering, erected from 7 October, to contain the severe leakage. After that, in November and December, a series of some thirty iron collars, each some 21in wide, were bolted into position, unit by unit. This formed a ‘mini-tunnel’ c. 8ft in diameter within the larger tunnel. As the subterranean repairs progressed, watermen started running a private ferry service across the river, for which LCC provided the petrol for the boats until the tunnel reopened.
On 19 March 1941, another HE bomb exploding in the river cracked 60m of tiling in the crown of the tunnel. This was not as damaging as the previous strike, however, and the tunnel was patched up and reopened the following day. Nevertheless, it was decided that no attempt should be made on any more permanent repairs until after the war. Yet some seventy years later, the iron-collared ‘temporary works’ are still in place, still marking the location of that HE bomb-strike on Black Saturday, 1940.
Greenwich Foot Tunnel. Opened in 1901, this tunnel allowed workers from Greenwich to get to the docks and factories on the opposite shore; the glass dome of the Island Gardens end of the tunnel can be seen to the right of the working wharves. (©Museum of London: PLA Collection 322072)
Mending the roof: iron collar inserted into the foot tunnel in 1940 to plug the breach caused by bombing in the Blitz. (Thames Discovery Programme)
Detail of segments of the custom-built collar, bolted together in 1940, still functioning in the Foot Tunnel eighty years later. (Thames Discovery Programme)