One of the local organisers said that they could not recall a time when the lecture theatre - which officially holds 185 people - had been so full.
It was all the more remarkable given that it was being used for a meeting called - deep breath - A Town Meeting to discuss UK Strategy for a Research Computing Ecosystem and the Future of e-Science.
As a rule: meetings that mention 'UK Strategy', 'Computing Ecosystem' and - especially - 'e-Science' do not attract huge numbers of people. This one was special because, somehow, the organisers had persuaded every branch of that amorphous thing called e-Science to come along.
There were the people from PRACE - who provide the really big compute for solving really big problems - and people who run the Institutional High Performance Computing services that drive so much UK research. We had the big data brigade - from Bioinformatics and Earth Systems science - who feed new research. We had representatives from research computing services, institutional IT services and the JANET network. We had the academics who push the limits of what you can do with a computer.
And, of course, there were representatives of the Grid - including the NGS, the Particle Physics community and less-traditional-users such as biology.
And everyone in the room agreed on what we needed to do.
I'll repeat that.
Nearly 200 people involved in academic research gathered in a room and unanimously agreed on what we needed to do next.
That is `what we needed to do' not `how we were going to do it'.
Everyone agreed that 'e-Science' must be driven by what the people who do the research actually need.
Everyone agreed that training for researchers is vital.
Everyone agreed that well-written robust software leads to better research.
Personally, I would like to have heard less agreement and more discussion. The e-Science community is full of people who have tackled difficult problems - sometimes successfully, sometimes less so - but the town meeting was simply too large scale for discussions.
Technical discussions are best served by gathering small groups of well informed people. They can get quite heated, but this is not necessarily a bad thing. The Moonshot meeting the day before was about the right size.
That is not to say that the discussions - heated or otherwise - did not happen. It just that they happened outside the meeting, by the coffee urn, or in the pub, or on the slow train home - between smaller groups of people who happened to be in London at the same time for a big meeting with a very unwieldy name.
If you weren't among the attendees, you can find some of the presentations on meeting's web page and follow the collective twitterings of some of those who were.