If we had a fair, proportional electoral system we'd have 25 MPs in Westminster. Just imagine it, Caroline Lucas 25 times over! But since we don't, we've got to be more creative - find ways to give more people roles and prominence.
They say in politics you should never say 'I told you so.' But I was reminded yesterday of a phrase I've often used: "the future of politics doesn't look like the past." I don't say it now, because it is a statement of the obvious.
One of the things I've always tried to do, and encourage others to do, is celebrate our victories. We've led on 20mph speed limits, on the living wage, on taking air pollution seriously. And we've made progress on all of those issues.
And in the news in the past 24 hours, we've seen two victories for our causes. One's small, but important - the government has finally, belatedly, announced a ban on microbeads in cosmetics.
The other's big, really big - the US and China have jointly ratified the Paris climate deal. That makes Theresa May's abolition of the department of energy and climate change, and her appointment as Environment Secretary of Andrea Leadsom look very out-of-step, very out-of-date, very dangerous.
If we're not to be entirely left behind Britain must also ratify the climate treaty now. If China and the US can do it, those two great polluters, we certainly can.
Once again we're the trailblazers in British politics
As you might expect, I've been reflecting back over not just my past four years as leader, but over my 11 years as a member of the Green Party. That's included 21 conferences and nine major elections.
Elections are like we wish buses were - they just keep coming along. But they're also like buses in that they don't always keep to the timetable - something we need to keep in mind in the coming months. Internal elections also just keep coming, and I want to congratulate all of the internal election winners, but particularly Caroline and Jonathan.
When I became leader of the Green Party in 2012 it was historic - the first time a woman had taken over from another woman as a leader of a political party in British history. Now the Green Party has made history again, with the first job-share leadership.
Once again we're the trailblazers in British politics, proving that the Green Party really does do politics differently - cooperatively, collegiately, working together for the common good. That's what I've experienced through the four years of my leadership - massive support, great help, loving care in the tough times and the good.
I've often needed your support. For in the Green Party, although we're now a major part of the political landscape, we're still operating with a fraction of the resources of those we're challenging.
To do my job I've had to rely on thousands of unpaid volunteers - volunteers who've worked out itineraries, guided me, dealt with the press, written briefings, put me up in their spare rooms. I couldn't have done it without you - thank you! These have been four wonderful years, both for me, and for the Green Party.
We won more votes than in every previous general election added together!
It is worth reflecting on your achievement in the 2015 general election. You won more votes - 1.1 million - than the Green Party in every previous general election added together. We contested 93% of seats, with 535 candidates, and saved 126 deposits. (In 2010 we saved just six.) That was symbolically and practically important - it saved us £63,000.
In four years as leader I've travelled up and down the country. I really should have kept track of my train miles. A journalist asked me this week if I'd ever sat on the floor of a train carriage. Have I ever? I've been getting more passionate about bring the railways back into public hands about three times a week.
My recent memorable train journey was going to the wonderful Hen Harrier Day at Edale, with eight hours on trains for three hours on the ground. I'd do it again tomorrow. For a ban on driven grouse shooting wouldn't just protect our majestic hen harriers, but also the ecology of our uplands, and the flood-threatened communities below them.
The past four years have, however, for British politics, society and our precious natural world, been awful years. The British people last year were stuck with a Tory government backed by only 24% of eligible voters. And the Conservative 2015 manifesto, which assumed we'd remain part of the EU, is now irrelevant. And there's no democratic guidance on what 'Brexit' means.
Theresa May has no democratic legitimacy. She has no right to proceed without a general election. She's in that position after what the Electoral Reform Society judged a referendum campaign that failed to meet basic democratic standards.
The understandable anger of voters at the state of the nation found an outlet. Brexit is the collateral damage from fire rightly directed at the British political class.
The Green voice in politics has never been more important!
Globally, over the past four years, well: Donald Trump's a huge worry but Jill Stein and Bernie Sanders are signs of positive change.
Renewable energy has surged ahead in much of the world, the concept of the universal basic income has moved from the fringe very firmly into mainstream debate. But one thing's clearer by the moment: Britain needs the Green Party, the world needs its Green parties.
Increasingly voters are recognising that. In Germany the Greens are part of more state governments than Angela Merkel's CDU. In Australia, the Greens won 10% of first preference votes - but under the Alternative Vote system still only one seat. Remember the hashtag - #AVisnotPR.
Britain and the world need not just Greens offering good ideas, campaigning for them and waiting for others to get the message. Britain, and the world, needs to stop electing the wrong people, then hoping they'll do the right things. On councils, in national governments, we must elect more, lots more, Greens.
The county council elections next May will be a great chance to do that - I'm confident we can win our first council elections in May in Wales and in many parts of England, and grow our representation on councils where we've only recently gained footholds.
And we've got a great chance to get the Green message out in upcoming 'metro mayor' elections. We don't agree with the Osborne plan but the elections give us the chance to explain what genuine local power and decisionmaking could look like.
I'm delighted to congratulate our Liverpool candidate, announced yesterday. Tom Crone's going to be great. And we know that he, and all of our candidates, have the message that people want to, need to, hear.
We are the only truly 'realistic' party
For the Green Party message of economic and environmental justice is the message for today. It brings the promise of jobs that people can build a life on, the security of the universal basic income and thriving communities built around small independent businesses and cooperatives.
The environmental crisis extends far beyond climate change: plastics in the oceans, destruction of our soils, biodiversity loss. These crises are a huge threat, but also an opportunity: in making the necessary radical changes to our society to heal our environment we can also build a better, more secure, life for everyone.
What's clear is that we cannot continue as we are. If someone tells them Green plans are 'unrealistic', look them straight in the eye and say: "You're the unrealistic one. Dream on if you think we can continue as we are."
The need for Green politics was clear in the referendum debate. Our Greens for a Better Europe campaign provided positive, effective messages, addressing issues from workers' and human rights to the environment, passionately defending the way in which free movement in Europe enriches all of our lives.
And that's something that we'll continue doing, and continue presenting the facts, not the lies that continue to be casually presented, on immigration and other European issues.
The real issue is not immigration
Last week I was at the French Greens Summer University. I was telling Greens from across Europe an important fact about the referendum. Something they need to know and that we need to stress in Britain. People did not vote Leave primarily on the basis of opposition to immigration.
Lord Ashcroft's detailed study shows that half of Leave voters said the biggest single reason was "the principle that decisions about the UK should be taken in the UK". It was only one third who cited their main reason for voting leave "as control over immigration and borders".
The many politicians, quite a few of them from the Labour Party, who are going around saying "this was a vote about immigration and it shows we have to stop free movement" need to be challenged. Strongly. This was not 'a vote against immigration'.
And even those voters who say they're concerned about immigration, when you ask them to explain, most talk about low wages, crowded schools and hospitals, the cost of housing. Those are all rightful concerns. But they are caused by the failed policies of privatisation, of austerity, of financialisation of our economy, of centralisation on Westminster. They are not caused by immigration.
The Brexit hashtag #takebackcontrol sums up the reason why people voted to leave - they were saying they didn't feel in control of their own lives, their own communities, their own futures.
And that's no wonder when we've got giant, market-dominating companies casually failing to pay their workers the supposedly legally binding minimum wage. They are parasites, tax-dodgers sucking huge profits from our society without paying for the infrastructure essential to generating them.
Time to #takebackREALcontrol
To restore trust, restore democratic control, to stop the plutocrats, what we need is a fair electoral system, a system in which people can vote for what they believe in, and get it. A proportional electoral system: that has to be the key goal, the change on which the essential political, social, economic and environmental transformation can be built.
In the 'mother of all parliaments', it's time to get democracy!
On a global scale, 'take back control' could also be the hashtag for another critical issue of the coming year - nuclear weapons. We've lived under the threat of nuclear annihilation for three generations. And the world's said enough. One hundred and thirty eight countries have signed up to work for a global ban on these hideous weapons of mass destruction.
In Britain, with Trident renewal on the horizon, we've got a unique opportunity to make a huge global impact with our policies, not simply to replace our 1% of the world's nuclear weapons, the weapons that from one submarine could kill 10 million people.
Let's join with the majority of the people of the world, take back control and ban nuclear weapons.
No, I will not be joining Ed Balls on Strictly Come Dancing
Lots of people are of course asking what I'll do next - now I'm no longer Green Party leader.
Well I'm going to let you into a long-hidden secret. In primary school a boy who hated being partnered with me in folk dancing lessons complained I had 'rusty joints' - and that became my nickname.
So I promise you, I'm not going to follow Ed Balls on to Strictly Come Dancing. What I will be doing is getting out on the picket lines supporting our junior doctors. Jeremy Hunt says what they're planning is the worst strike in NHS history. Well he's got the something right - the adjective. He's the worst Health Secretary in the history of the NHS.
He really should take English lessons. Jeremy, a contract is an agreement, not something you impose!
What I'll also be doing in the coming weeks and months is campaigning on education. Students in schools, colleges and universities have told me how they feel failed, damaged, by an education that prepares them for exams, not life, that puts crushing pressure and fear of failure into young lives.
The Green Party education policy - abolishing SATs and the awful phonics test, getting rid of Ofsted, and of course abolishing tuition fees and restoring maintenance grants - is wonderful. And it's up to all of us to ensure that every pupil, every teacher, every parent - everyone who cares about the future - knows what it is.
I'll also be campaigning for the restoration of cultural education and cultural funding. Drama, music and art are essential parts of a healthy society. And given the importance of these sectors of the British economy, is plainly, simply stupid.
I'll also be campaigning also to highlight the abject, total failure of the Thatcherite policy of the privatisation of public services. For we know - it's demonstrated by the failure of the Labour Party to back the NHS Reinstatement Bill championed by Caroline Lucas - that the Green Party is the anti-privatisation party.
We're the people who say that prisons, courts, policing, military activities should not be in private hands. The coercive power of the state should never be privatised! We're the people who consistently resisted the privatisation of the Royal Mail, who understand that privatisation is built on cutting the level of services, slashing the pay and condition of services, and shovelling public money into private hands.
I'm standing down as Green Party leader. But I'm not going away
So I think you've got the picture. I'm standing down as Green Party leader, but I won't be going away. If we had a fair, proportional electoral system we'd have 25 MPs in Westminster. Just imagine it, Caroline Lucas 25 times over! But since we don't, we've got to be more creative - find ways to give more people roles and prominence.
My title will be 'former leader', but the reality is that I'll be joining you all in being leaders - for every member of the Green Party is a leader.
You're helping lead Britain, and the world, away from the destructive, inhumane, unsustainable politics of the past four decade, towards a society, a world, that works within the environmental limits of our one fragile planet while delivering a decent life for everyone.
You're making a difference in your community - as a councillor, as an organiser, as a talker and a doer - people who together can transform our society.
Thank you for everything you've done, and everything you're going to do. I look forward to what we can achieve, united, together.
Natalie Bennett is the former leader of the Green Party of England & Wales.
This article is the very slightly edited text of Natalie's speech to the Green Party conference on 3rd September.