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Impartial Assessments Ltd



We are a London-based consultancy providing UK-wide unexploded ordnance (UXO) desktop study services to the construction industry. 

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why choose us

risk assessments you can trust 

Unlike most of the competition, we generate 100% of our revenue through desktop risk assessments. As we do not benefit from recommending risk mitigation measures, you can be certain of our impartiality.

Impartiality: it's in our nature, it's in our name.  


quality and accuracy 

Every risk assessment draws on over a decade of research into the UK's buried UXO landscape.

Always aiming to obtain every relevant primary source record - our philosophy is leave no stone unturned. 

Therefore, you can be confident that your 'Impartial Assessment' is both comprehensive and accurate. 


best practice

Our assessments comply with the relevant industry (CIRIA) guidelines on UXO risk.

With a focus on transparency, our semi-quantitative risk model is based on a traditional contaminated land style risk assessment.  


green credentials 

It is our goal to make Impartial Assessments Ltd a net zero company.

Go for the responsible option with one of the UK's greenest explosive ordnance risk assessment providers.

Interested? Get in touch to find out about our minimal carbon footprint. 

why choose us


'Very impressed with the professional approach that Impartial Assessments undertake on their risk assessments'.

Alex M - Associate Director at WS

'Impartial Assessments provide desk based UXO support on all my team's projects, where this service is required. They are an invaluable part of our supply chain, providing expert, pragmatic advice to agreed timescales, enabling us to proceed with ground investigations safe in the knowledge that all potential UXO risks have been assessed, not only to the highest of standards, but from a truly impartial perspective'.

Tom - Associate Director at Delta-Simons

'Oliver and his team have helped us out on approximately 25No. jobs and we always get a professional service. Being able to separate SI risks from that of the larger development risks has not only helped us to reduce the overall costs of a project, it’s also looked on very favourably by the client, instead of the assumption that onsite mitigation is required'.

Ryan - Senior Geotechnical Manager at Ecologia Environmental Solutions 

'Impartial Assessments have been used to successfully refine and revise UXO risk assessments (conducted by others) of tricky sites, and as such have earned their place as our preferred supplier of desk based UXO risk assessments'.

Tom - Director at Geosphere Environmental 

'Impartial Assessments is Evolve’s ‘go to’ for UXO assessment. Their prompt and valuable advice ensures that we can be reactive to our client's requirements, in the knowledge that the advice provided remains utterly and always impartial. Their breakdown into separate ground investigation and development risk assessments is a great and useful tool’.

Paul Bennett - Director at Evolve Geo-Environmental 

'Impartial Assessments have continuously provided technically excellent, professional and cost-effective UXO risk assessments to support our Site Investigations. Most importantly, they approach every assessment with an open mind, and are dedicated to providing accurate and unbiased results. Their commitment to transparency is commendable and highly valued by Roberts Environmental'.

Ben Lawry - Associate Director at Roberts Environmental 

'I have worked with Oliver and the team at Impartial Assessments since 2021 and have always found their service to be of a high standard coupled with an excellent knowledge of all things UXO. Also of importance to me is their USP of only providing desk based risk assessments'.

David Jackson - Principal Engineer and Geo-environmental Consultant

What our clients think about us



the founder

Oliver has over 13 years' experience researching and writing UXO risk assessments. Having headed up the research departments of two established UXO specialist companies, he is one of the UK’s most experienced explosive ordnance (EO) risk assessors.


There really is no substitute for experience when it comes to understanding buried EO / UXO risk in the U.K. Only through years of academic work, locating and analysing various written records, maps, aerial photographs, historic incidents, recent UXO finds etc, can one develop a broad appreciation of the types of relevant primary source evidence and the myriad factors that influence the likelihood of EO contamination at a given site.

'Impartial Assessments was born out of frustration with the status quo. I wanted to provide a fresh alternative with a focus on accuracy, proportionality and trust'


'During my career I have written and signed off over 3,000 desktop studies, including many large, complex projects both in the UK and overseas'.

Oliver Brown - Managing Director

the team 

The research team is based in the City of London, the epicentre of the World War 2 bombing campaign against Britain. Darryn King and Isaac Naylor have several years experience as EO researchers / risk assessors. 

The research team, which is supported by our administrator Grace Storm, also has access to explosive ordnance disposal (EOD) engineer consultancy.


Preliminary Risk Assessment 

Providing an initial screening and placing your site in context with regards to buried explosive ordnance (or UXO) risk. Swift and inexpensive, our preliminary assessments are the ideal first step. 

Detailed Risk Assessment 

A comprehensive report providing the most accurate assessment of risk to your ground works, based on thorough project-specific research. The 'best practice' option.

Risk Assessment 

Peer Review 

We are proud to offer a successful peer review service. Through rigorous research and deep understanding, our trusted second opinion could substantially reduce your or your client's costs.



What is unexploded ordnance (UXO) and explosive ordnance (EO)? 

Explosive ordnance is a broad term that describes all items that contain explosives or biological or chemical agents, including individual components containing explosives. UXO is explosive ordnance which has been prepared for use and fired, launched, or dropped, however failed to function as designed. German unexploded bombs (UXBs) dropped during WW2 are the most well-known type of UXO in the UK.

Do I need a UXO risk assessment?

There is no UK law specifically requiring you to undertake an explosive ordnance risk assessment before breaking ground. However, general health and safety laws (1974 and 1999) as well as industry specific CDM2015 regulations require consideration of all known risks. Explosive ordnance is one such risk.

How frequently are unexploded German bombs found in the UK?

On average, the 11 Explosive Ordnance Disposal Regiment deals with five large German high explosive bombs, forty 1kg German incendiary bombs and three 2kg incendiary / high explosive bombs every year (source: MOD). Note, the most numerous 1kg bombs are significantly less hazardous than the other two types.     

Does UXO actually pose a risk?

If struck with sufficient force, UXO has the potential to detonate. However, fortunately, inadvertent UXO explosions in the UK are rare and all recent incidents in Europe have occurred outside of the UK. The most recent UK incident occurred in June 1995 at the MOD’s Merrivale Training Area (Dartmoor), where three children were seriously injured when a 2-inch mortar projectile exploded. 

My site's location was not heavily bombed during WW2. Presumably the UXO risk to my ground works will be low?

The vast majority of UXO encountered in the UK is not of German origin. During WW2, over 4,000,000 hectares of UK land were in use with British and Allied armed forces. CIRIA estimates that approximately 20% of the UK's land mass has seen some form of military activity at some stage. As of 2017, the MOD’s training estate covers around 364,000 hectares. The only way to be sure of identifying historic military activity at your site is to carry out an explosive ordnance risk assessment.

My site was redeveloped post-WW2. Presumably the UXO risk to my ground works will be low?  

Not necessarily. The larger German unexploded bombs (500kg+) could penetrate to depths of >10m bgl. Such UXO could conceivably remain undisturbed during the post-war construction of a multi-storey building with a double level basement and piled foundations. In February 2020 a 500kg German UXB was encountered during construction works in Soho. Following severe WW2 bomb damage, a five storey building was built on top of the bomb during the 1950s. 

The building on my site survived WW2 intact. Presumably the UXO risk to my ground works will be low?

Not necessarily. Large unexploded German bombs did not penetrate the ground vertically, instead they produced a curved path through the soil. This ‘J-Curve Effect’ resulted in a lateral offset of several meters, from point of entry to final resting position. Consequently, German UXBs striking ruins, dense vegetation, bodies of water etc could come to rest beneath neighbouring structures that sustained little or no damage. 



head office

7 Bell Yard, Holborn, London WC2A 2JR


tel:        0207 126 8164

             office hours: 08:30 - 17:00  

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