Tony Cliff. Palestinian Jew, Revolutionary Socialist d. 9th April 2000. Nothing So Romantic
Tony Cliff, real name Ygael Gluckstein was a leading figure in the International Socialists and UK Socialist Workers Party.
Below is link to an interview he gave to Nicholas Walter in 1970. It is interesting exposition of Cliff’s thinking though of its time.
The opening exchange goes:
Your name is not in fact Tony Cliff. Why do you find it useful to use a pseudonym?
I worked for 13 years in illegal conditions in Palestine under British rule and there we had to use pseudonyms, and I think it just became habit forming.
It isn’t part of the Bolshevik tradition, this use of pseudonyms?
No, I don’t think it came from that, nothing as romantic.
https://www.marxists.org/archive/cliff/works/1970/06/interview.htm
Kmflett's Blog 
I enjoyed reading this. My memory of Tony Cliff dates from the 1970’s when he stayed overnight at my house. My bedroom was above the lounge so this made it difficult for me to get a good nights sleep with Cliff and my dad talking all night, Yes, all night!
Despite their political differences, my dad always spoke respectfully and warmly about him.