Unexploded bombs: Is your site at risk?

It seems not a week goes by without news of the discovery of an unexploded wartime bomb is making the headlines. 

Just last week, a bomb was identified on a development site in Cheylesmore near Coventry, where work is taking place to develop new student accommodation close to Coventry University. With a specialist bomb disposal team drafted in, it took 28 hours for the one-tonne bomb to be safely removed, creating much disruption and uneasiness in the local area.

Other finds within the past couple of months – all of which were discovered on building sites – have included Bethnal Green, Wokingham, Westfield shopping centre in Shepherd’s Bush and a site near Wembley Stadium, to name but a few.

For every major unexploded ordnance (UXO) story such as these, there are numerous smaller discoveries across the UK on a weekly basis that often go unreported in the media. The reality is that even 70 years on from the end of the Second World War, UXO presents a serious threat on all UK construction projects. 

Critical advice

Such is the threat that the Construction Industry Research & Information Association published guidance on assessing UXO risk on sites. The guidance recommends conducting a preliminary risk assessment for UXO on all sites as a matter of course. And just because your building project is located outside of a major city, don’t think you won’t be affected by wartime bomb risk. 

In fact, the wartime activities of the Secret Intelligence Service – a predecessor to MI6 – meant that decoy airfields, military bases and factories were constructed and, in many instances, placed on official maps. The intention was to lure Luftwaffe’s bombs away from the industrialised cities and crucial military targets, and instead towards rural areas. 

Even after the war, the deception continued as RAF aircrews were commissioned to create a post-war aerial photo record of Britain. Photographs were manipulated and sensitive facilities were replaced with open fields (complete with grazing cows) and cloud cover. Such practices continued through the Cold War years to today and the upshot is that across the UK, there are many sites for which a true record of their past land use does not exist within the publicly available records. 

Do your research

This means that, irrespective of whether it is in an industrialised city or in open countryside, any site in the UK can pose a potential risk from UXO, so it is wise for preconstruction due diligence to take place at the outset of any project.

This will require a review of historical mapping; however, just because it is mapped does not mean it is entirely accurate. Consider what additional contextual information might be available and relevant to your site and how might you go about obtaining it.

The financial implications of discovering a UXO on a project can be significant and the more accurately we can pinpoint potential risk on a project, the more effectively it can be managed and mitigated.

By Piers Edgell, Senior Account Manager at Landmark Information Group