Now he is determined to make them. Just because he was a Jewish prisoner of the Nazis when he performed his labours does not, he believes, exempt them from that duty. "They exploited us," he said.
Last week, at a meeting in north London, dozens of the former labourers heard details of a campaign to gain redress for that exploitation - of meetings with the German and American ambassadors and talks with lawyers.
Mr Kennedy, 69, is one of at least 170 men and women in Britain who were forced to work for the German war effort. It was an alternative way of killing them, for the average life expectancy of a slave labourer was just three months.
Mr Kennedy was 15 when he was sent to the Auschwitz concentration camp and set to work for a firm called IG Farben building a road.
"The temperature was about minus 10C. We were given wooden clogs but no socks, no underwear. We were freezing," he said. "I realised I couldn't survive it for very long."
After three weeks, his father managed to get them into an Auschwitz factory making electronic circuits for, he has since established, Siemens. "I think I had one more week to live at that point," he said.
They worked 12-hour days on a piece of bread and two bowls of watery soup which gave them diarrhoea. The only protein they could get was the occasional worm.
Then, in January 1945, they were moved again, to work in Volkswagen's underground factories manufacturing the V1 "doodlebug" bomb and the V2 rocket.
Mr Kennedy ended the war a tubercular skeleton in Belsen. Although he later escaped to Britain and built a successful career as an electronic engineer and a businessman, the scars remain.
It was a recent visit to Auschwitz that made him reconsider his ordeal. "I had neglected for 50 years really talking about it. But I had promised my father on his deathbed that I would not forget it," he said. "I decided I had to do something."
He helped found the Claims for Jewish Slave Labour Compensation Association. It is not dedicated to helping the needy as such, but to securing payment for the work its members carried out. They believe it is their right.
Mr Kennedy is unusual in knowing who he worked for. He has even received a small sum of money - around pounds 500 - from IG Farben.
But many slave labourers have received nothing, while the companies they worked for prospered.
Many of the firms argue using slave labour was not their choice, although the Nuremberg trials decided to imprison the heads of some of the biggest - Flick, Krupp and IG Farben - as war criminals.
The source of the survivors' anger lies in the post-war negotiations, which agreed slave labourers were not entitled to compensation until there was a final peace treaty. Thanks to the Cold War that was never signed, leaving a legal escape clause.
Nevertheless, some firms gave money to the body set up to handle compensation, the Conference on Jewish Material Claims Against Germany. But most specified it should help Jewish organisations, not just individuals.
Mr Kennedy's group fears the claims conference is failing to represent its interests. A claims conference spokesman said it was a delicate matter. "I think they have every right to be angry, but not at us," he said.
However, its board has decided to make the slave labourers a priority. It is also pinning further hopes on the precedent set by Volkswagen, which announced last month that it would, in principle, pay compensation.
There are signs that the final accounting of the Holocaust now taking place might also help.
Just as Swiss banks have come under pressure, some believe German firms may have to do more for the slave labourers, or face international opprobrium.
The campaigners are certainly determined. In the words of another labourer, Roman Halter, at the meeting last week: "If we have to crawl on our knees because we can't walk any more, we will see that justice is done."Reuse content