UXO Risk in Cardiff

UXO City Guide

Home Office Bombing Statistics for Cardiff

Record of German Ordnance dropped on the County Borough of Cardiff

High Explosive Bombs (All types)

536

Parachute Mines

26

Oil Bombs

0

Phosphorus Bombs

0

Fire Pots

25

Pilotless Aircraft (V-1)

0

Long-range Rocket Bombs (V-2)

0

Weapons Total

587

Area Acreage

14,050

Number of items per 1,000 acres

41.7

Why was Cardiff targeted and bombed in WWII?

On the face of it Cardiff may not be considered the most obvious place to have been targeted for sustained bombing, with bigger and more industrially important cities such as London, Birmingham, Coventry and Hull at the forefront of the Luftwaffe’s attention.

However, due to Cardiff containing one of the biggest coal ports in the world during a time where coal was an essential fuel resource – Cardiff docks were targeted heavily during WWII. The Welsh city was not just important for industry, commerce and trade but was also crucial for much needed supplies to reach Britain from across the Atlantic during WWII.

Luftwaffe target photography of Cardiff (South). Image credit: Imperial War Museum

Home Office Bombing Statistics for Cardiff

Over the course of the war, air raid sirens were sounded 585 times in Cardiff, with a total of 355 people killed and 502 people injured.

Details recorded by the official Home Office bombing statistics, indicates the volume and type of bombs that fell on the County Borough of Cardiff throughout WWII.

A total of 587 recorded bombs fell on Cardiff, equating to 41.7 items of ordnance per 1,000 acres.

Major bombing raids on Cardiff

While the last few months of 1940 brought several bombing raids over other Welsh towns and cities, the most devastating attacks on Cardiff came on 2nd January 1941. The full moon or ‘Bomber’s moon’ that night, set the stage for the worst bombing Wales had experienced to date.

The wail of the air raid sirens was soon followed by the sound of bomber aircraft over the city as they crossed the Severn estuary. The first bombs struck at 6.37 pm and continued to fall over a period of ten hours¹.

Damage to Llandaff Cathedral after the Luftwaffe bombing raid – January 1941. Image credit: Wales Online

Bomb damage on Craddock Street, Cardiff – February 1941. Image credit: Glamorgan Archives

Around 150 people were killed and dozens of buildings and homes were destroyed – and the day is commonly referred to as the Cardiff Blitz (due to the German ‘Blitzkrieg’, meaning ‘Lightning War’).

This included major Cardiff landmarks such as Llandaff Cathedral, which sustained extensive damage to both the church itself and its immediate area due to multiple parachute mines being dropped in its vicinity.

Bomb damage on St Agnes Road, Cardiff – 1941. Image credit: Glamorgan Archives

Aerial image showing damage caused to Cardiff after a bombing raid – January 1941. Image credit: Welsh Government

Further examples of the volume of ordnance dropped on the city can be found in a localised incident within the Riverside community of Cardiff. This air raid took place, once again on 2nd January 1941, killing 50 people on De Burgh Street².

Fortunately, local bombing incidents were recorded with some examples shown in the damage damage map below.

This National Fire Service sketch highlights bomb hits immediately north of Cardiff docks during a raid in May 1943. Image credit: Internal Resource

Can UXO still pose a risk to construction projects in Cardiff?

Yes – UXO can still present a potential risk to construction and development projects in Cardiff.

The primary threat comes from German air-delivered bombs dropped during WWII that failed to detonate as intended. It is estimated that around 10% of munitions deployed across the UK did not function correctly. Although significant wartime and post-war bomb disposal operations were carried out, not all unexploded bombs (UXBs) were located or removed.

Ongoing discoveries of UXO during intrusive groundworks across the UK continue to demonstrate that buried wartime ordnance remains a potential risk – including in areas such as Cardiff.

I am about to start a project in Cardiff, what should I do?

Before any intrusive groundworks begin, developers, principal contractors, and ground investigation teams should assess potential UXO risk through either:

This forms the first stage of an effective UXO risk mitigation strategy and should be undertaken as early as possible in the project lifecycle, in line with CIRIA C681 guidance.

Why does an early UXO Risk Assessment matter?

Where a credible risk is identified, appropriate mitigation measures should be implemented to reduce risk to As Low As Reasonably Practicable (ALARP).

Equally, unnecessary mitigation can create avoidable project costs, delays and operational disruption.

A professional UXO Risk Assessment will make sure:

Site-specific threats are properly identified.
Appropriate mitigation strategies are recommended.
Unnecessary mitigation measures are avoided.
Projects remain compliant, safe and commercially efficient.

Early-stage UXO Risk Assessments help developers make informed decisions, protect personnel, maintain compliance and avoid unnecessary expenditure.

If you are planning development or intrusive groundworks in Cardiff, obtaining a professional and unbiased UXO Risk Assessment should be your first step.

Sources

^{1https://www.bbc.co.uk/news/uk-wales-11609989}
^{2https://www.walesonline.co.uk/lifestyle/nostalgia/night-second-world-war-bombs-8358790}

Recent UXO discoveries in Cardiff

Since the war, many items of UXO have been discovered across multiple cities within the UK, with Cardiff no exception. See the news articles below about UXO incidents and discoveries from national and local press in Cardiff.

1st Line Defence keep up-to-date with relevant and noteworthy UXO-related news stories reported across the UK, and you can browse through these articles using the buttons below.

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