Two prominent former refuseniks paid tribute to Soviet Jewry activist Michael Sherbourne and told Limmudniks of their prison “romance” communicating only in morse code through pipes.

Jewish Agency director Natan Sharansky and rabbi and writer Yosef Mendelevitch requested a minute’s silence at the beginning of their session in memory of Mr Sherbourne who died at the age of 97 earlier this year.

Mr Sherbourne was a British soldier who used his knowledge of Russian to act as communicator between refuseniks in the USSR and Western activists in the 1970s.

Mr Sharansky, returning to Limmud after his debut last year, said: “It is hard for people to believe this one man changed the world.

“He made thousands of calls every day, sending telegrams, trying to avoid the KGB, then getting the information and sending it to different Jewish organisations around the world.

“Michael was our internet and TV. He was this one man who made sure every day there was a connection between us and the Jewish world.”

Mr Mendelevitch, famous for his involvement in a plane hijacking plot in 1970 to raise awareness of the plight of Soviet Jewry, said: “Michael was very stubborn - to call again and again you have to be. I believe the people on the other side of the telephone were the same kind of stubborn. To never get disappointed is a very specific trait.”

The writer of Unbroken Spirit told the audience of around 70 people that a fitting tribute to Mr Sherbourne would be to carry on his tradition of activism.

“The best memory is to do whatever he did: to be stubborn in activism, in the struggle for Israel and Jewish education. Be insistent and we will achieve,” he said.

Mr Sharansky, who was incarcerated for a time in the same Soviet prison as Mr Mendelevitch, jokingly described their relationship as a “romance”.

He said: “We communicated in morse signals - because we were afraid of being caught by guards. We never met. Then one day we met because the guards made a mistake. Prisoners were supposed to take a walk one by one in the yard. But they made a mistake and we both ended up taking a walk at the same time. Before the guards could come and stop us we jumped on each other like lovers”.

The pair also ingeniously managed to communicate through the plumbing.

“To speak through the toilet you take the water out and put your hand deep inside and you can speak through the pipe,” explained Mr Mendelevitch.