A secret code-breaker working for British Intelligence had a brush with Ruislip’s famous Soviet spies – without even realising it.

At the start of the Cold War, Sergeant Russell Barnes worked at the Government Communications Headquarters (GCHQ) site in Lime Grove, Eastcote, intercepting German and Russian coded messages.

He had joined the Intelligence Corp at GCHQ from the army in 1948, remaining there until 1952, taking Russian lessons and working on deciphering coded messages.

Officers stationed at Eastcote were permitted to use Swakeleys House in The Avenue, Ickenham, which was at that time under the Foreign Office.

“We spent a lot of our relaxation time at Swakeleys House,” said Mr Barnes, who nowadays lives in Dorset. “We had a rugby team and a cricket team, and I was part of a jazz band.

“I have always been extremely passionate about music. Jazz has been a lifetime interest for me,” he said.

It was because of his interest in music that he somehow fell into a conversation with one Morris Cohen, known at the time by his alias, Peter Kroger, and working as an antiquarian book dealer.

Mr Kroger and his wife Helen – real name Lona Cohen – were in fact Soviet spies, communicating with Moscow from the attic of their modest bungalow in Cranley Drive, Ruislip.

They were arrested alongside three others in January 1961 for their part in the Portland Spy Ring.

Spies Peter and Helen Kroger on their way to Heathrow after their release from prison

A shocked Mr Barnes then realised this was the man he had contacted some time before, looking to further his hobby.

“Because of my interest in music I was looking in the Yellow Pages one day and noticed an antique book collector living in Ruislip,” he said.

“I phoned the number to see if he was selling any music books or sheet music. I started talking to him, but I noticed he had a slight accent.

“I asked him about it, and he hung up on me – he wasn’t interested in continuing that conversation.

“I thought no more about it until I saw on the news that a couple in Ruislip had been arrested as part of a spy ring.

“I realised: ‘That’s the man I was talking to’.”

While at GCHQ Mr Barnes and his fellow officers did not wear uniforms and lived among the community.

He said: “I was in Linden Avenue in Ruislip Manor with three US Navy officers in one of the bungalows.

“Only our landlady knew who we were - most people thought we worked for the Civil Service.”

Among the men he served with in Eastcote were Alexander Bennett who, after military service, built his international career as a dancer with the Ballet Rambert company and Roger Hancock, the brother of comedian Tony Hancock, who later became a talent agent.

Mr Barnes' No 4 Intelligence Company colleagues relaxing after a game of tennis at Swakeleys House, Ickenham, in 1950

After leaving the army, Mr Barnes, who lives in Blandford Forum in Dorset, worked as a police officer for 11 years but later in life formed the Blandford Jazz Circle, organising concerts with leading world-famous jazz musicians.

Before it became GCHQ, the top-secret site Mr Barnes worked on in Eastcote was known as HMS Pembroke Park V and was an outstation of Bletchley Park, playing a significant role in deciphering enemy signals during the Second World War.

It is now a housing estate named Pembroke Park and residents honoured the site’s important history unveiling a special plaque on Thursday, November 20.