When Mr Harris beckoned me over to their table, he was holding his arm upright as three members of City Hall staff mopped up a bloody cut on his hand.
"That was from a community litter picking event, it's what happens when you try and do a good deed" he chuckled.
The 79-year-old Mayoral candidate is running for the Cannabis is Safer Than Alcohol Party and he wastes no time in telling me that their priority is to raise awareness for the legalisation of cannabis.
Once upon a time a prohibitionist working to ban the drug from Britain, Mr Harris said he know realises as long as it is in controlled doses, is "as relaxing as a cup of tea".
"I used to see these young girls when I first moved her with dilated eyes and taking a lot of pills, it was that Mod era, so I worked to help bring in the Misuse of Drugs Act.
"But now I want to put it right, I was such a moral crusader back then."
Partied with the likes of John Lennon
Sat beside him, one would never think this grandfatherly figure once partied in the early hours of the night in London's west end wearing what he described as "flowers in my hair and a kaftan", meeting the likes of Yoko and John Lennon and Beat generation writer Allen Ginsberg.
Now a Londoner for around 60 years, he admitted he had always had an interest in politics, from storming Downing Street in protests to selling political newspapers in Johannesburg, where he was born.
"I came here on a ship from Cape Town to Earl's Court. I still remember I used to walk through the streets here and say London belongs to me."
Born Jewish but now a Buddhist, the candidate said the drug is important for medical use and insisted its explored much more from what he saw when he visited Israel, particularly for epilepsy.
It's not just the medicinal purposes, but the crime which he feels could be resolved by legalising it, because "prohibition means greedy dealers introducing skunk".
'Young people shouldn't take it'
When I asked him about the research which shows cannabis can be dangerous, particularly for those with mental health issues, he replied, "Well, young people shouldn't take it.
"But alcohol's a gateway drug. Cannabis relaxes people and I think it's less violent.
"There will always be substance abuse, nothing is completely safe, bu if you control it, it's better.
"People should be allowed the freedom to make mistakes, if you make things unattainable, people find worse ways of getting hold of it."
The party strongly support the notion that regulating, controlling and taxing cannabis could make the city safer and increase funds for City Hall - and they had to convince signatories from each borough to agree before submitting Mayoral papers.
"That was funny, we managed to get over 60 flats in the Barbican area to sign as soon as we explained what we stand for."
"I'm too frightened to tell people I was Jewish"
Drugs aside, what would happen if Mr Harris found himself to be Mayor of London?
"Renewable energy is very important and we need to think about the city's future" he said.
"I also think we need to protect London villages from gentrification."
On west London, Mr Harris said the infrastructure is totally wrong and should he become Mayor, he would completely overhaul transport systems across the city.
Londoners must have more compassion for one another, he explained
"I also think the Afro-Caribbean community deserve an apology for the stop-and-search experiences they have had" he told getwestlondon.
"I have a lot of love from the African community."
Mr Harris said addressing the divisions between communities is crucial as it has led to home grown terrorism.
The Mayoral hopeful explained that as a Buddhist, he hates prejudice against religion and urges Londoners to conquer hate and have compassion for one another.
Fleeing from apartheid himself before settling in London's Portobello Road running an alchemy store, he said he has grown up seeing division and only in unity do good things happen.
"We must heal the wounds of our dividing society where some are poor and others are incredibly wealthy. One love."
