Election 2015: Will Green 'revolution' take off?
There was one man from east London in a Green Party T-shirt and maybe a handful of other supporters but otherwise, no sign in the room of the "Green surge" the party is so proud of.
Natalie Bennett, the party's leader, said membership had reached 59,000 and to help get that message across, some of their names appeared on the posters used as the backdrop for today's manifesto launch.
Printed as an "executive summary" to save paper, the manifesto sets out the party's programme to create "a more equal, more democratic society while healing the planet".
The Greens call it a "peaceful revolution" but it's an expensive one too. Their proposals include plans to increase government spending by an additional £177bn a year by the end of the next parliament.
By 2019 government spending will be around 20% higher than it's forecast to be for the year 2015.
The Greens don't like being drawn into the same tax-and-spend scrutiny of the other parties but they know economic credibility matters. So they've tried to answer the question about their sums adding up.
Their spending plans will be paid for, they say, by tax increases and growth that comes from creating one million new jobs.
They admit though, that they aren't sure how much their wealth tax would raise as it hasn't been tried before.
At today's press conference Natalie Bennett brushed away questions about their plans for pensions by telling the audience to check on the website where the full manifesto is published.
Whatever the uncertainties, the Greens believe their pitch - anti-austerity, outside the mainstream, environment-friendly - is winning support.
They're fielding a record number of 535 candidates in England and Wales.
Caroline Lucas was their first MP, elected in 2010, and is seen as an effective spokesperson. The Greens' big priority is to retain her Brighton Pavilion seat and they are targeting 12 others, including Norwich South, Bristol West and Oxford East.
By contrast, Ms Bennett has had to live down the catastrophic interview she gave London-based LBC radio at the launch of the election campaign in January. Since then, she has appeared more confident although her personal rating didn't improve after the first TV debate.
Could the Green Party influence the next government? They have ruled out any arrangement that props up a Tory administration.
If Labour leads the next government, then the Greens say they would be prepared to offer support on a vote-by-vote basis. But the conundrum they face is that Labour plans spending cuts - more austerity - which the Greens say they want to end.