Historical overview


Sources of unexploded ordnance

Guidance to the industry is provided by the Construction Industry Research & Information Association, CIRIA, in the form of their publication: C681 Unexploded ordnance (UXO), a guide for the construction industry.  This advises that there are three main sources of UXO on constrution sites are:

  • ordnance resulting from wartime activities
  • munitions deposited as part of military training exercises,
  • munitions that were deliberately dumped or accidentally left behind.


Our guidance and experience

The information that we have provided on our website describes the main geographical areas and reasons that UXO is likely to be found on UK construction sites.  This list is based on our experience working in construction related roles and through research we have completed. 

The CIRIA guidance states that two UXO clearance companies found 15,000 significant items of ordnance on construction sites in a three year period. This figure is remarkably high and does not represent the vast majority of the UK's construction sites.  Unfortunately, this statistic is often used by the media and some UXO clearance companies, which we believe misrepresents the facts.

We have provided additional information on the following sources of UXO in the UK and geographical areas where it is possible ordnance may be be found.  They are:

  • WW1 aerial bombing
  • WW2 aerial bombing
  • former airfields
  • bombing decoy sites
  • training areas
  • defensive positions
  • munition factories
  • aircraft crash sites
  • inaccessible areas and quarries.


We hope that you will find our website interesting and informative, allowing you to put the risk of UXO on construction sites within context, but it cannot be taken as advice nor a professional opinion.  

If you are concerned about the risk of UXO on your site, we would advise that you contact a competent risk assessor.  

If you want unbiased advice - contact us!


There is relatively little video footage of bomb disposal operations shortly after WW2, however these two clips show incidents in the years after the war.

London, 1949

West India Dock, 1956