That really surprised me too. In my experience there certainly isn't any shortage of web startups in London, so I have to wonder why so few of them come to an HN event.
Off the top of my head, possible options:
1. Startups don't engage on HN, or don't feel part of the community. This seems pretty unlikely.
2. (London) HN readers are predominantly people in full time jobs, or just not entrepreneurial.
3. Startups are too busy working.
But none of those seem particularly probable. Maybe it is a cultural difference?
Off the top of my head, possible options:
1. Startups don't engage on HN, or don't feel part of the community. This seems pretty unlikely.
2. (London) HN readers are predominantly people in full time jobs, or just not entrepreneurial.
3. Startups are too busy working.
But none of those seem particularly probable. Maybe it is a cultural difference?
Or maybe it was just a bad night for startups :)