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Chrishall Observation Post

by | Aug 28, 2019 | Mill Causeway, Wartime | 0 comments

Observation post

On the corner of Hertford Lane, is Chrishall Observation Post. It is a concrete structure, fairly substantial but also fairly well hidden in the undergrowth and hedging that grew up around it. 

The article below, written by Stephen Foote for the village magazine, outlines its purpose.


Not recorded on County or District databases – but listed in the records of the recent English Heritage ‘Defence of Britain’ survey co-ordinated by the Imperial War Museum at Duxford, is a Royal Observer Corps (ROC) observation post on the corner of Hertford Lane near Crawley End. It’s English Heritage monument number is 1412499.

Almost completely hidden in undergrowth now, this building was an aircraft observation post, built of pre-cast concrete sections in the early 1950s. It was used by volunteer members of the ROC to monitor aircraft movements and report them back to a central control post by telephone.

The post was a two-floored building. The lower floor, built slightly below ground level, was simply an accommodation for the observers in bad weather. It is not high enough to stand up in. The upper floor was the ‘observation platform’. A steel tube, about 2 inches in diameter, securely fixed to the foundations of the building, passes through the ceiling of the lower floor to protrude about 3 feet into the upper floor. The tube terminates in a round flange about 4 inches in diameter. This was the mounting for the ‘post instrument’ – a device for measuring the height and direction of travel of the observed aircraft.

I discussed the post with a former Chrishall resident whose father and grandfather were both in the ROC and he remembered them manning the post during those years. All the volunteers were local people.

Towards the end of the 50s, as the Cold War deepened, the government concluded that the new threat required new duties for the ROC, to report on and co-ordinate civil and military activities in the event of a nuclear strike by the Warsaw Pact. To this end some 1,500 underground observation bunkers were constructed across the UK, all reporting to central control posts.

In many cases these bunkers were constructed on, or near to, the sites of existing observation posts but for some reason this did not happen in Chrishall. The ‘powers that be’ built the underground bunker for the area in a field off Quickset Road, between Elmdon and Ickleton where it remains to this day. A new aircraft observation post was built beside it; it is built of brick rather than concrete sections.

The Ickleton underground bunker came into service in July 1959. For a short while the Chrishall post and the Ickleton bunker were manned simultaneously but before long Chrishall was abandoned and the volunteers concentrated their efforts at Ickleton. The Ickleton site was in turn abandoned in 1967.

The Chrishall post is in good condition albeit surrounded by undergrowth and almost invisible in the summer. It is something of a rarity; very few of these buildings have survived. The door of the shelter is gone and the ladder to the observation floor likewise, but the ‘post instrument’ mounting tube is still extant, and there are some remnants of corrugated iron sheeting lying close by which could be parts of the 3-section corrugated iron cover that used to be fixed over the observation floor of these posts as protection from the weather when the post was unmanned.

Connections to the telephone pole close by the post was probably the means of communication with the ‘outside world’ but the telephone wires from the pole now run below ground and there is no trace of a telephone connection on the post itself.

We would be very pleased to hear from anyone who has any recollections (or photographs) of either the Chrishall observation post or the Ickleton underground bunker from earlier years, or can correct any errors of fact in this short record.


You might also enjoy Joe Hagger’s article about actually being part of the Observation Corps and manning the Chrishall observation post which is available by clicking here.



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