Higher Education Minister David Lammy was among the special guests as a Golders Green club for Orthodox boys celebrated its move to new premises.
Chaverim has taken over a former Kwik Fit outlet with plans to turn the site into a community centre.
The club incorporates a computer centre, library, lounge and pool, snooker and table tennis tables.
It runs activities for all ages between seven and 25 and has 1,800 members. Over 200 people attended the official opening.
Trustee Avi Werjuka said: "The site was going to be turned into offices, which I thought was a shame as it's in the centre of a Jewish area. We are now renting it with an option to buy and have converted a quarter of the site to be used by the club.
"We are hoping the rest of the site will be used as a community and sports centre, incorporating Chaverim."
A planning application was being formulated and funding options pursued.