To watch my speech forward video to 1 hour 47 minutes in.

My 'maiden' speech given today at 3.30pm in the House of Commons.

A maiden or first speech is seen as quite a big event as far as MP protocol goes.

Here's what I said:

Mr Speaker,

I am most grateful to you for calling me during today's debate.

The environment is a subject dear to my heart, as I'm sure you know, and I'll return to it in a moment.

I think anyone would find their first speech in this chamber daunting, given its history and traditions, and the many momentous events it has witnessed.

But I have an additional responsibility, which is to speak not only as the new Member of Parliament for Brighton Pavilion, but also as the first representative of the Green Party to be elected to Westminster.

You have to go back several decades, to the election of the first Nationalist MPs in Scotland and Wales, to find the last maiden speech from a new national political party.

And perhaps a better comparison would be those first Socialist and Independent Labour MPs, over a century ago, whose arrival was seen as a sign of coming revolution.

When Keir Hardie made his maiden speech to this House, after winning the seat of West Ham South in 1892, there was an outcry.

Because instead of frock coat and top hat, he wore a tweed suit and deerstalker.

It's hard to decide which of these choices would seem more inappropriate today.

But what Keir Hardie stood for now seems much more mainstream.

Progressive taxation, votes for women, free schooling, pensions and abolition of the House of Lords.

Though the last of these is an urgent task still before us, the rest are now seen as essential to our society.

What was once radical, even revolutionary, becomes understood, accepted and even cherished.

In speaking today, I am helped by an admirable tradition - that in your first speech to this House, you should refer to your constituency and to your predecessor.

David Lepper, who stood down at this election after thirteen years service as Member for Brighton Pavilion, was an enormously hard-working and highly-respected Member whose qualities transcend any differences of Party.

I am delighted to have this chance to thank him for his work on behalf of the people of Brighton.

It is also a great pleasure to speak about Brighton itself. It is, I am sure, well-known to many Members, if only from Party conferences.

My own Party has not yet grown to a size to justify the use of the Brighton Centre, although I hope that will change before long.

But I can say to honourable members who are not familiar with it, that it is one of the UK's premier conference venues; and there are proposals to invest in it further to help ensure that Brighton retains its status as the UK's leading conference and tourism resort.

There are also the attractions of the shops and cafes of the Lanes and North Laine, the Pier and of course the Royal Pavilion itself, which gives its name to the constituency.

And beyond the immediate boundaries of the constituency and the city, there is the quietly beautiful countryside of the South Downs and the Sussex Weald.

Brighton has always had a tradition of independence - of doing things differently. It has an entrepreneurial spirit, making the best of things whatever the circumstances, and enjoying being ahead of the curve.

We see this in the numbers of small businesses and freelancers within the constituency, and in the way in which diversity is not just tolerated, or respected, but positively welcomed and valued.

You have to work quite hard to be a "local character" in Brighton.

We do not have a single dominant employer in Brighton. As well as tourism and hospitality, we have two universities, whose students make an important cultural, as well as financial, contribution to the city.

There are also a large number of charities, campaigning groups and institutes based there, some local, others with a national or international reach, such as the Institute of Development Studies, all of which I will work to support in my time in this place.

I would like also to pay tribute to those wonderful Brighton organisations that work with women. In particular I'd like to mention Rise, who do amazing work with women who have been victims of domestic abuse.

Many of my constituents are employed in the public and voluntary sectors. They include doctors and teachers, nurses and police officers, and others from professions that do not always have the same level of attention or support from the media, or indeed from politicians.

But whatever the role - social workers, planning officers, highway engineers or border agency staff - we depend upon them.

I'm sure that members on all sides would agree that all those who work for the State should be respected and their contribution valued. In a time of cuts, with offhand comments about bureaucrats and pencil-pushers, that becomes yet more important.

There is also a Brighton that is perhaps less familiar to honourable members. The very popularity of the City puts pressure on transport and housing and on the quality of life.

Though there is prosperity, it is not shared equally. People are proud of Brighton, but they believe that it can be a better and fairer place to live and work.

I pledge to everything I can in this place to help achieve that, with a particular focus on creating more affordable, more sustainable housing.

Brighton was once the seat of the economist Henry Fawcett who, despite his blindness, was elected there in 1865. Shortly afterwards he married Millicent Garrett, later the leader of the suffragists, a movement he himself had supported and encouraged.

So he lent his name to the Fawcett Society, which is still campaigning for greater women's representation in politics.

The task of ensuring that Parliament better reflects the people that it represents remains work in progress - and as the first woman elected in Brighton Pavilion, this is work that I will do all that I can do advance.

I said when I began that I found this occasion daunting.

Perhaps the most difficult task is to say a few words about the latest radical move that the people of Brighton have made - that is, to elect the first Green MP to Parliament.

It has been a long journey.

The Green Party traces its origins back to 1973, and the issues highlighted in its first Manifesto for a Sustainable Society - including security of energy supply, tackling pollution, raising standards of welfare and striving for steady state economics - are even more urgent today.

If our message had been heeded nearly 40 years ago, I like to think we would be much closer to the genuinely sustainable economy that we so urgently need, than we currently are today.

We fielded fifty candidates in the 1979 general election as the Ecology Party, and began to win seats on local councils. Representation in the European Parliament and the London Assembly followed.

Now, after nearly four decades of the kind of work on doorsteps and in council chambers which I am sure honourable members are all too familiar, we have more candidates and more members, and now our first MP.

A long journey.

Too long, I would say.

Politics needs to renew itself, and allow new ideas and visions to emerge.

Otherwise debate is the poorer, and more and more people will feel that they are not represented.

So I hope that if, and when, other new political movements arise, they will not be excluded by the system of voting. Reform here, as in other areas, is long-overdue.

The chance must not be squandered. Most crucially, the people themselves must be given a choice about the way their representatives are elected.

And in my view, that means more than a referendum on the Alternative Vote - it means the choice of a genuinely proportional electoral system.

Both before the election and afterwards, I have been asked the question: what can a single MP hope to achieve? I may not be alone in facing that question.

And since arriving in this place, and thinking about the contribution other members have made over the years, I am sure that the answer is clear, that a single MP can achieve a great deal.

A single MP can contribute to debates, to legislation, to scrutiny. Work that is valuable, if not always appreciated on the outside.

A single MP can speak up for their constituents.

A single MP can challenge the executive. I am pleased that the government is to bring forward legislation to revoke a number of restrictions on people's freedoms and liberties, such as identity cards.

But many restrictions remain. For example, control orders are to stay in force. Who is to speak for those affected and for the principle that people should not be held without charge, even if it is their own homes?

House arrest is something we deplore in other countries. I hope through debate we can conclude that it has no place here either.

A single MP can raise issues that cannot be aired elsewhere.

Last year Honourable Members from all sides of the House helped to shine a light on the actions of the international commodities trading group Trafigura, and the shipping of hazardous waste to the Ivory Coast.

There was particular concern that the media in this country were being prevented from reporting the issues fully and fairly.

This remains the case, for new legal actions concerning Trafigura have been launched in the Dutch courts, and are being reported widely in other countries, but not here.

Finally, I would like to touch on the subject of today's debate.

I have worked on the causes and consequences of climate change for most of my working life, first with Oxfam - for the effects of climate change are already affecting millions of people in poorer countries around the world - and then for ten years in the European Parliament.

But if we are to overcome this threat, then it is we in this chamber who must take the lead.

We must act so that the United Kingdom can meet its own responsibilities to cut the emissions of carbon dioxide and other gases that are changing our climate, and encourage and support other countries to do the same.

This House has signed up to the 10:10 Campaign - 10% emissions reductions in 2010. That's very good news. But the truth is that we need 10% emission cuts every year, year on year, until we reach a zero carbon economy.

And time is running short. If we are to avoid irreversible climate change, then it is this Parliament that must meet this historic task.

That gives us an extraordinary responsibility - and an extraordinary opportunity.

Because the good news is that the action that we need to tackle the climate crisis is action which can improve the quality of life for all of us - better, more affordable public transport, better insulated homes, the end of fuel poverty, stronger local communities and economies, and many more jobs.

I look forward to working with Members from all sides of the House on advancing these issues.