Fellows discovers grenade at Thames Tideway Tunnel site

During a recent survey for the ongoing Thames Tideway Tunnel (TTT) project, Fellows discovered a potentially hazardous hand grenade and took steps to identify and isolate the item so it could be dealt with by the Metropolitan Police service’s Explosive Ordnance Disposal (MPS EOD) unit.

The grenade was spotted by Fellows UXO Engineer Steve Lakeman as he conducted a low-tide survey walk of the foreshore adjacent to the TTT project’s Heathwall pumping station location.  Identified as a ‘Mills’ hand grenade, which were in use with British and allied forces in 1918, the device is thought to have been a No. 36 variant. If live, it would contain approximately 70 grams or explosive with a lethal range of 30 metres and a danger area from fragmentation of up to 100 metres.

Due to corrosion and partial encasement in concrete, it was not possible to ascertain whether the pin was still in place, although the fly-off handle was clearly in situ showing the grenade had not been thrown.  Therefore, Fellows instigated procedures for a potential explosive hazard, surrounding the device with sandbags and identifying its location with a marker pole to ensure it could be found easily by the bomb disposal team as the tide would rise before the they could remove it for off-site disposal.  Further advice was issued to TTT personnel in case of any incident in the meantime.

The condition of the grenade indicated that it had been in the water for some time and was likely a discarded war souvenir or unknowingly delivered to the site in imported materials. Such finds are not uncommon in areas with significant military history like London and, as a result, Fellows’ low tide surveys will continue at the site until work reaches a point where risks are no longer posed.

The Thames Tideway Tunnel is a major new sewer construction project for the capital, urgently needed to protect the tidal River Thames from pollution.  Scheduled for completion in 2023, the project aims to tackle the problem of overflows from Victorian sewers for at least the next 100 years and enable the UK to meet European environmental standards.