Now aged 99 and living in a one-bedroom flat in Edgware, he says he will raise a glass of whisky to colleagues who have the distinction of being the last army still fighting in the Second World War, and "fighting to the last".
He had qualified as a solicitor at 21 and set up his own practice shortly before war broke out in 1939. He enlisted a year later. "It was what I wanted. I felt I had to do my job as a Jew," says the former national chairman of the Association of Jewish Ex-Servicemen and Women.
"We had a Jewish refugee's hostel for girls near us, so we knew what was happening in Germany. I would see them being brought over on the Kindertransport and I couldn't ignore it.
"I wanted to fight and I didn't want to wait to be called. I wanted to decide what unit to serve."
His first posting was to a field artillery regiment at Redcar racecourse, just 40 miles from where he lived.
In 1942 he was sent on his first overseas posting to Nigeria where he was seconded to the Royal West African frontier force. It was there that Mr Cohen, who was keen on retaining his Jewish identity, earned the nickname "the white Muslim" as he took command of a unit of Muslim troops. He even did his best to learn their language, Hausa, and taught them English in return.
He says: "My unit was Two Five One West African Heavy Anti-Aircraft Regiment" he recalls with ease. "Eighty per cent were Muslims and there was I, a Jewish officer, and there was no problem at all.
"I spoke about the Obah Ibrahim [Father Abraham] and they thought it was wonderful. They didn't know what a Jew was. I was fortunate as I had two English teachers in my troop and they helped me teach the Nigerians. "It made sense, because as good as it was that we spoke their language, if we were killed they would have had new commanders come in who couldn't speak to them.
"It came to be an advantage later on because I would use passwords in Hausa that would not be easily translated. We taught them everything on the guns and after 12 months it was time to take them overseas."
Despite his increasing responsibilities as a commander, he tried to observe the Jewish festivals, and with the help of a Jewish doctor from Stamford Hill, he organised a service for Yom Kippur.
He says: "We ordered machzerim but it got sunk by a German submarine. We wrote out the Kol Nidre from memory - and when we checked back years later we realised we had only made three errors. "
Mr Cohen left Nigeria in 1943 having trained his unit as part of the 14th West African AA Brigade, on a trip that finally saw them docked in Bombay.
He said: "We stopped several times on the way, once in Cape Town - but we soon realised that was just for wine. We had little idea of where we were going until we got there.
"It was a surprise to end up in Bombay. We took the train across India; these were no express trains as you can imagine. From there we went to Assam, and finally Burma where I stayed until November 1945."
With the war in Germany ending three months earlier, Mr Cohen said: "We felt we were part of the forgotten war. We were out in the bush. We didn't have TV or newspapers, we were alone.
"Everyone at home was celebrating and we were still out there fighting in conditions you couldn't imagine.
"Not only did we have to fight the Japanese but we also had to fight against the climatic conditions and the tropical disease."
He said: "It wasn't until my birthday on August 6, 1945, that I received the best present anybody could receive: the first atomic bomb was dropped on Hiroshima, and that was virtually the end of the war."
Mr Cohen arrived home in November and was mentioned in dispatches for services in Burma.
On his return he resumed his legal career. He says: "I became very involved with the community, especially my synagogue, but in 1947 the Territorial Army was reformed and they needed people like me with my experience."
After two years he was promoted to major and in 1954 he was made a lieutenant colonel. Today, he says nothing is more important to him "than seeing the community recognise VJ day.
"When we are no longer here we want our children and grandchildren to remember what we did so they can live free in this country."
And when he has that whisky - a large one - he said he will "think about how I felt at the time, which was, 'wonderful! This is the end'."
Watch Mordaunt Cohen talk about his experience in his own words:
