In a room packed with supporters, Jeremy Corbyn looked happier than he has for weeks.
Delivering his first campaign speech, he was fired up against the wealthy and the powerful, who he described as a "cosy cartel hoarding this country's wealth for themselves" and rigging the system against ordinary people.
Westminster was probably not the ideal setting for his pitch as the champion of the dispossessed.
But he railed against a Conservative party "hell-bent on cutting every public service they can get their hands on".
And he didn't leave out the pesky media and Establishment who keep asking him about Labour's position in the polls.
That position has deteriorated further today with a YouGov survey putting the Tories on 48% - a staggering 24 points ahead of Labour. These are numbers we have not seen since 2008.
But although several of his MPs have already announced they will quit politics rather than fight a losing battle in their constituency, he insists the election is not a foregone conclusion.
For Labour to win an overall majority they not only need to keep the seats they currently hold, but win 100 more.
It's a formidable task, so what can the Labour leader do?
In these circumstances, Mr Corbyn is trying to make the best of it by branding himself as an insurgent, and an underdog.
As someone who has little to praise about the last Labour government and voted against it at almost every opportunity - despite borrowing their slogan "the many not the few" - it's a pitch he can carry off.
Asked about the dire predictions today, he pointed to his victory in the Labour leadership contest in 2015, claiming his odds were 100/1 but he still managed to win.
There has been speculation his team is eyeing the Donald Trump playbook in his attacks on the media and rage against the status quo. And look what happened to him.
Mr Corbyn is concentrating on the domestic front - the NHS, wages and inequality.
His party remains divided on Brexit, and the Labour leader dodged a question from Sky News on whether he would rule out a second referendum on Britain's deal with the EU, before ruling it out hours later.
His hope is to run a campaign that is authentically him and "close to the people", as an ally described it.
One Labour source contrasted his appearance in a high street in Croydon this week with Theresa May "going by helicopter to a private members' club".
The policies are fairly populist - free school meals funded by a VAT hike on private school fees, and a £10 minimum wage by 2020 - and he stresses they are fully costed.
Even his tax plans, as set out at present, are not as radical as some of his supporters might like. Many of them are popular with floating voters, until they realise who is championing them.
His close team believes he can convince the electorate at large with the same strategy he used to win over the half-a-million strong Labour membership.
As the Conservative attack machine is just getting into gear, Jeremy Corbyn needs to show his demoralised party that if his leadership only lasts another seven weeks, he will go down fighting.