Yes, it was illegal but you wouldn't think so if you visited certain areas. I won't go into all the details, but I remember on one occasion when I was on a training course (staying in the Heathrow hotel) we got talking to this Arab guy who was clearly packing a heavy wallet and he offered to take me and two others into London to "get some action".
So, we pile into this black cab and tell the driver what we were about, BUT he misunderstood the situation (four young men) and took us to this pub somewhere (god knows where) and as we entered it was absolutely packed from wall to wall with gay men.
The innocents that we were, we quickly high tailed it out of there and told the taxi driver what WE were looking for (birds of course) and he tried to set us up with some local "ladies of the night", but I think our age was agin us and the "adventure" fizzled out back at the hotel.
It was an experience I will never forget.