These ranged from disquiet over economic policy, anger at the banking system and bankers' remuneration and bonuses, the continued war on terror and concerns over climate change.

Their 12-point economic plan for democratic governance demanded democratised financial institutions to deliver secure jobs and public services, an end to global poverty and inequality, and a green economy.

[11] Several hundred people joined a peaceful Stop the War Coalition march from the American embassy in Grosvenor Square to Trafalgar Square[12] which brought together protesters from the Stop the War Coalition, Palestine Solidarity Campaign, The British Muslim Initiative, and the Campaign for Nuclear Disarmament.

[18] "Spiderman", the French climber Alain Robert, climbed the Lloyd's building and unfurled a banner saying "100 months to save the world" in reference to the urgency of tackling climate change.

At a rally in Hyde Park, they were addressed by Global Call to Action Against Poverty co-chair Kumi Naidoo, TUC General Secretary Brendan Barber, environmentalist Tony Juniper, activist comedian Mark Thomas, and global justice author Susan George amongst others.

[20] The Put People First alliance of more than 160 unions, development, faith and environment groups called on the G20 leaders to recognise that "only just, fair and sustainable policies can lead the world out of recession, and that a return to 'business as usual' – with the associated poverty, inequality and climate change – is not an option".

Christian NGOs including World Vision and Tearfund organised an ecumenical service on the day at Methodist Central Hall, overseen by the Bishop of London.

Delegations joined the march from around the world, including Belgium, Czech Republic, France, Germany, Hungary, Italy, Luxemburg, Netherlands, Portugal, Romania, Slovenia, Spain, Korea, USA, Australia, South Africa, Zambia, Canada and the Philippines.

[27] The windows of a branch of the Royal Bank of Scotland were broken by a group of protesters at 13:45,[24] some of whom entered the building and looted office equipment and papers and threw smoke grenades, chairs and eggs[28] There was intense media attention to this event, with a ring of photographers surrounding the people breaking the windows[29] and David Howarth MP later commented that one of the unresolved mysteries of the day was why the moment that a masked person threw the first piece of scaffolding through the window it was observed by hundreds of photographers and film crews already in position.

"[36] Without alternative facilities, people used the entrances to Bank Underground station as a urinal,[26] although the police said that temporary toilets and water were made available to protesters.

[38] A video of the raid allegedly shows an officer pointing a Taser at protesters who are lying on the floor, which would be against police guidelines.

[42] The "Camp in the City" (51°30′55″N 0°04′57″W / 51.5152°N 0.0825°W / 51.5152; -0.0825) on 1 April 2009 aimed to draw attention to carbon trading, claiming that far from being a way of reducing release of climate change gasses in the atmosphere it is used as an excuse to continue doing just that.

Scotland Yard confirmed that a meeting was to take place with police Commander Bob Broadhurst and Chief Superintendent Ian Thomas.

[48] The atmosphere was still relaxed at about 5 pm when police with helmets, shields and batons began to surround areas of the camp using section 14 of the Public Order Act 1986.

[49] The police advanced on protesters who put their hands in the air and passively resisted while chanting "This is not a riot",[50] a tactic that emerged over the course of a number of Camp for Climate Action gatherings.

They said that the level and style of activity on the internet suggested a re-emergence of groups with similar aims to the anti-globalisation protesters who turned to violence in 2000 and 2001.

[61] Including a number of raids on squats on 2 April 2009, the police made over 100 arrests and said they had identified and would track down those who had broken the law.

[64] One raid on a climate change group the day after the main protests was ruled to have been illegal in March 2010, the Met Commissioner said that it was unlawful to arrest and search protestors and to force them to be recorded on film.

David Howarth, a Liberal Democrat MP, said: "I am increasingly worried that what the police are saying about the protests will end up in a self-fulfilling prophecy.

[73][74] An officer is being investigated and has received a written warning after writing "Rob Ward can't wait to bash some long haired hippys up @ the G20" as a Facebook status update on the evening of 1 April.

The City of London police asked them to leave the area at the Royal Exchange for half an hour, and threatened arrest if they refused.

Sir Ken Jones, the President of the Association of Chief Police Officers, has criticised the lack of objectivity which he perceives has been shown by the media.

[78] Home Office minister Lord West of Spithead said in the House of Lords that "thousands of officers acted absolutely professionally and proportionately, thousands were actually able to demonstrate peacefully on our streets, criminal activity in the rest of the metropolis was kept to an absolute minimum and the police also maintained high levels of security.

"[72] The Mayor of London, Boris Johnson, has defended the police,[81] and said that "I worry that there are large sections of the media that are currently engaged in a very unbalanced orgy of cop bashing".

A sergeant with the Territorial Support Group is seen slapping a woman who was arguing with him, Nicola Fisher, across the face, then striking her legs with his baton.

Sir Paul stressed that all uniformed officers must wear shoulder identification numbers to be easily identifiable by the public.

[88] On 14 April 2011 the high court has ruled that the Metropolitan police broke the law in the way they "kettled" protesters at the G20 demonstrations in 2009, and also criticised the use of force by officers.

[89] Ian Tomlinson, a newspaper vendor in the City of London, died within a police cordon of the G20 Meltdown protest near the Bank of England.

Days later, The Guardian published video showing Tomlinson had been pushed by a Metropolitan Police Service officer and hit with a baton minutes before he collapsed and died.

[90] The results of this second post mortem have revealed that Tomlinson actually died from an abdominal haemorrhage caused by the baton strike.