RAF Stoke Hammond
By Nick Ellins
May 2021
RAF Stoke Hammond came about as the allied nations endured the darkest days of the Second World War, and needed to increase their intelligence for enemy activity taking place in the Middle and Far East.
Across the globe, military agents and resistance groups scanned the airwaves to locate and write down enemy communications. They listened in the original language and codes of the enemy, and then retyped and transmitted what they heard in the same coded form to the UK, via agreed frequencies at set times and by using high speed Morse code.
This activity became known as the ‘Y service’. The name came from a simple phonetic representation of the words ‘Wireless Interception’ or WI.
RAF Stoke Hammond would act as the final collecting point, or Y network terminal, for the highly sensitive information coming through. Working almost exclusively for the Government Code & Cypher School at Bletchley Park, it was staffed entirely by RAF personnel at both ends and operated in total secrecy. Bletchley Park relied on its wireless interceptions to give it the core material to decode.
Bletchley Park used RAF Stoke Hammond as its key receiving station for this network and RAF Greatworth (near Brackley) for the transmitting side. The three sites together were set up in a specific and closed unit under the RAF No.26 (Signals) Group called 372 Wireless Unit.
RAF Stoke Hammond was built across 1942, commissioned in February 1943 and came in to full service in March 1943. This was timed to allow it to work with the newly built Bletchley Park Communications Centre sited in the Block E Auto Room.
The personnel at Dorcas Lane:
The received transmissions then went automatically down a dedicated landline straight in to Bletchley Park for decoding and analysis.
Wireless operators and aerial technicians worked in shifts throughout the day, seven days a week with just half a day off duty each week. There was limited accommodation in Nissen huts on the Dorcas Lane site, but from October 1943, they were mainly housed at RAF Church Green next to Bletchley Park itself and transported in to Dorcas Lane each day.
The workload was high, requiring 24 wireless operators and 11 wireless operator mechanics. By 1944, with a total headcount of nearly 60 people were required to operate the site, and around 75 high frequency receiver masts sat in the Dorcas Lane fields.
When the Second World War ended, Bletchley Park closed quickly.
RAF Stoke Hammond kept its important role however, and it was placed under the strategic control of the fast evolving RAF Leighton Buzzard (renamed RAF Stanbridge) as the Government and military focus moved to tackling what would become known as the Cold War.
RAF Stoke Hammond maintained its role as a highly secret wireless network terminal right across the conflict, doubling the capacity of its wireless receiver buildings, and also becoming the global centre of excellence for the calibration of all RAF transmitters.
As global political tensions eased and communications technology rapidly moved on, the need for wireless interception reduced and services were steadily outsourced. By the autumn of 1973, RAF Stoke Hammond was effectively closed after three decades of covert service for the nation. The same fate would eventually befall most of the similar sites, including RAF Stanbridge which finally shut in 2013.
By Nick Ellins
May 2021
RAF Stoke Hammond came about as the allied nations endured the darkest days of the Second World War, and needed to increase their intelligence for enemy activity taking place in the Middle and Far East.
Across the globe, military agents and resistance groups scanned the airwaves to locate and write down enemy communications. They listened in the original language and codes of the enemy, and then retyped and transmitted what they heard in the same coded form to the UK, via agreed frequencies at set times and by using high speed Morse code.
This activity became known as the ‘Y service’. The name came from a simple phonetic representation of the words ‘Wireless Interception’ or WI.
RAF Stoke Hammond would act as the final collecting point, or Y network terminal, for the highly sensitive information coming through. Working almost exclusively for the Government Code & Cypher School at Bletchley Park, it was staffed entirely by RAF personnel at both ends and operated in total secrecy. Bletchley Park relied on its wireless interceptions to give it the core material to decode.
Bletchley Park used RAF Stoke Hammond as its key receiving station for this network and RAF Greatworth (near Brackley) for the transmitting side. The three sites together were set up in a specific and closed unit under the RAF No.26 (Signals) Group called 372 Wireless Unit.
RAF Stoke Hammond was built across 1942, commissioned in February 1943 and came in to full service in March 1943. This was timed to allow it to work with the newly built Bletchley Park Communications Centre sited in the Block E Auto Room.
The personnel at Dorcas Lane:
- tracked the set frequencies that Bletchley Park decided the listening stations should transmit on
- located the high speed Morse code once the transmissions started
- worked to maintain the integrity of the signal
The received transmissions then went automatically down a dedicated landline straight in to Bletchley Park for decoding and analysis.
Wireless operators and aerial technicians worked in shifts throughout the day, seven days a week with just half a day off duty each week. There was limited accommodation in Nissen huts on the Dorcas Lane site, but from October 1943, they were mainly housed at RAF Church Green next to Bletchley Park itself and transported in to Dorcas Lane each day.
The workload was high, requiring 24 wireless operators and 11 wireless operator mechanics. By 1944, with a total headcount of nearly 60 people were required to operate the site, and around 75 high frequency receiver masts sat in the Dorcas Lane fields.
When the Second World War ended, Bletchley Park closed quickly.
RAF Stoke Hammond kept its important role however, and it was placed under the strategic control of the fast evolving RAF Leighton Buzzard (renamed RAF Stanbridge) as the Government and military focus moved to tackling what would become known as the Cold War.
RAF Stoke Hammond maintained its role as a highly secret wireless network terminal right across the conflict, doubling the capacity of its wireless receiver buildings, and also becoming the global centre of excellence for the calibration of all RAF transmitters.
As global political tensions eased and communications technology rapidly moved on, the need for wireless interception reduced and services were steadily outsourced. By the autumn of 1973, RAF Stoke Hammond was effectively closed after three decades of covert service for the nation. The same fate would eventually befall most of the similar sites, including RAF Stanbridge which finally shut in 2013.