WWII Invasion Defences

Paulsgrove Spigot Mortar

 Created 22-06-2003    Last update 25-01-2007


Information arrives

Many people have e-mailed me about a "gun emplacement" to the east of Paulsgrove Chalkpit which they used to play in when they were children, and all references to its location tied up very nicely. Through the UK Fortifications Club I learnt that the emplacement was in fact a Spigot Mortar Weapons Pit and was last recorded in the mid 1980s. This was an important find, and had to be investigated further. During these investigations it became apparent that the whole area formed part of a World War Two anti-invasion defence site.


The search

 After numerous visits to the area, it appeared that the Weapons Pit did not exist any more (2003). However there are some clumps of very thick undergrowth around and with the help of a friend - Andy Martin - who just happens to be a tree surgeon we searched again. It could not be found and it must now be assumed that the site has been destroyed.


The Spigot Mortar

The Spigot Mortar or "Blacker Bombard" was invented by Lieutenant-Colonel Blacker with the aim of providing cheap and easily produced weapons after most of the British Army's heavy equipment had been lost at Dunkirk. Other field weapons invented for the same purpose during this period were the Northover Projector and the Smith Gun. It fired a 20lb fin-stabilised high explosive mortar bomb propelled by black powder, and had an effective range of 100yds in its anti-tank role and up to 450yds when firing a lighter anti-personnel bomb. It had one major drawback in that when the warhead hit its target, the fins would often fly backwards endangering the firing crew. 

In its static defence role, the mortar was mounted on a steel pin set into a substantial base of reinforced concrete. This was in turn set within a camouflaged weapons pit to offer some protection to the three man gun crew. A portable mount was also available, but weighed around 350lb and took 3 men to move it.

The spigot mortar was rejected by the regular army but saw service with Home Guard and airfield protection units from 1941-1944. 


Aerial photo site location    

Grid Ref SU639065

Visit this site - Portsdown Walk No2

  With thanks to:

 UK Fortifications Club, Andy Martin, Derek Britton, Mark Wallace, David Tabner

spigot mortar weapons pit

The only (photocopied) photo of the Paulsgrove Spigot Mortar Weapons Pit known to exist, taken in the mid 1980s. The cylindrical lump of concrete has a 29mm stainless steel pin set in it on which the weapon was mounted. The pin would have had a crown and crowsfoot stamped on it as it was regarded as part of the ordnance. The pit itself has been lined with concrete - the corrugated iron shuttering marks can still be seen. The shape of the pit allows room for the crew to maneuver and provides space for ammunition lockers. 

site of weapons pit

This is the area east of Paulsgrove Chalkpit where the Spigot Mortar was located. The edge of the Chalkpit can be seen on the upper left.

Copyright Derek Britton


 NEW - 25-01-2007

Spigot Mortar Front

An original Spigot Mortar at Tilbury Fort in Essex situated in a 6 inch gun emplacement. The curved steel armour plate behind the barrel was to protect the gun crew from the consequences of firing it.

Photo by: David Tabner


NEW - 25-01-2007

Spigot Mortat Rear

A rear view of the mortar shows the primitive aiming controls. The two  downward facing handles were used for direction whilst the straight bar protruding through the slot controlled elevation. A gunner would rest his forehead on the rest and take aim through the inverted 'T' slot. For an account of what happened next read the email from Harry Bradbury below.

Photo by: David Tabner

anti tank ditch

There is evidence of further anti-invasion defences in the area. Here is an anti-tank ditch above the Chalkpit. Portsmouth Harbour is in the back ground.

weapons pit

The arrow indicates a filled in weapons pit which would have had a good command of the high ground. The metal posts holding the expanded steel retaining walls can be made out. Research into this area is ongoing. 


 NEW - 20-01-2007


Going through the web site of Portsdown Tunnels under 'Invasion'  I came across the Spigot Mortar; the Blacker Bombard. During part of my time spent as a Private in the Chesterfield Home Guard I was in the Blacker Bombard Squad. However during my 5 years in the Army (infantry) nobody I spoke to had ever heard of the Blacker Bombard. Old soldiers I have spoken to since had never heard of it and I feel sure they thought that I was making it up. Thank you very much for providing the proof that there was such a weapon.

The base of the Mortar had four legs made out of 2 inch red band tube which slotted into the base of the Mortar itself. We were suppose to be mobile. When firing it we had to lay down and there was a padded roller at the end of the firing butt and you had to rest your head on this to look through the site. When you fired the thing the front end jumped up and the roller hit your forehead and nearly broke your neck. I only fired this contraption once thank goodness. The Blacker Bombard squad consisted of six men and a Sergeant. It was really the days of Dads' Army. At 18 I joined the real Army.

Harry Bradbury, Derbyshire - January 2007