G20 summit: Diary of a London green protestor

I am with the Green Horsemen of the Apocalypse - the 'Green Horse march' for short - who are protesting against environmental crimes. Our plan is to march down Bishopsgate to the Bank of England and later to join up with the Climate Camp protestors who plan to set up tents at 12.30pm somewhere in the City.

LATEST FILE:

3.19 pm, Bishopsgate. I've finally reached the Climate Camp. We're in the middle of Bishopsgate in beautiful sunshine among dozens of tents pitched in the street. It is a ludicrous but fantastic sight. Worth the wait.

2.45 pm, Mansion House Street. The police line has been broken by a massive crowd pushing out of the area in front of the Bank of England down Mansion House Street. Riot police tried to close the breach but didn’t have the strength in numbers. The crowd are setting the pace now and having broken through, they're wandering further into the City. The police don't seem to have anywhere to regroup to. The crowd is peaceful at the moment. Now the police seem to be forming a new line at the end of Queen Victoria Street.

2.16pm, Corner of Threadneedle Street and Bartholomew Lane. Lots of riot police after the attack on RBS. A large group of black-hooded protesters have headed to the front where riot police are waiting for them. The police on the front line won't evenacknowledge the protestors. Now the police horses have appeared and there’s red smoke in the air - I think it's a flare - and drum n bass playing over the sound system. Projectiles are flying over my head. Two-way traffic to and from the frontline as fighters rush forward and the rest steam back. Horrible atmosphere.

1.48 pm, Bank of England. The police are putting on their riot gear as windows are broken at the RBS branch next to the Bank of England. Not good.

1.10 pm, Bank of England. The best banner reads: 'Oi Jackie, we won't pay for your porn'. But things have turned nasty: the police dive into the crowd to arrest a punk. The crowd surrounds them, throwing objects. Lots of police run in to save their colleague. The drunk hooligan tendency is in full flow now and the police have been forced to react. The media is still everywhere.

12.55 pm, Bank of England. Bragg has played the famous anarchist anthem The Internationale on the steps of the Bank of England. Very fitting. Then everyone listened to King Tubby's Sound System. Now a football-style chant of 'Who are ya' has gone up against the police.

12.33 pm, Bank of England. Billy Bragg is putting on an impromptu concert. He's playing This Land is Our Land. It seems we're in for the long haul, and some of the tension has gone. Before Bragg began, a large drum group was belting out a samba while grim-faced

British Transport police looked on. At least we're having fun. The problem is we were supposed to be at the Climate Camp. No one knows how long we'll be stuck here.

12.05 pm, Bank of England. A group of 30 or so people, dressed totally in black suits and balaclavas, has suddenly emerged from the middle of the crowd. They have surged through the police line and disappeared.

12.02 pm, Bank of England. I can see two coffins being passed above the heads of the crowd. Allegorical I trust. There's a brass band playing - it's looking like a New Orleans funeral.

11.55 am, Bank of England. We're all in front of the Bank, hemmed in by police. 'Snatch squads' are diving from the police lines into the crowds to grab individual protestors.

11.45 am, Threadneedle Street. We have been hemmed in front and back by police. Some of us remember this was the same tactic the Met employed at a May Day march on Oxford Street a few years back. Some projectiles are flying, nothing serious.

11.37 am, Threadneedle Street. We're in sight of the Bank of England now. The police have formed their lines and they're pushing the media scrum back. Gradually we protestors are being let through but the police are maintaining a strict formation at the front and sides of the mob.

11.30 am, NatWest Tower. Police are operating two lines, one keeping members of the press away, one holding front of march back. It's edgy as hell but there's still no sign of riot police. Protestors are getting noisier, singing, booing bankers, playing instruments. There are a couple of very shouty trouble-makers at the front.

11:22 am, Liverpool Street station. The Green Horse march has left the back of Liverpool Street station, heading for the Bank of England. About 150 or 200 people have formed a relatively disorganised protest group, or flashmob. There is a heavy police guard at both the front and the back of the mob and officers have told us we will not be allowed to march onto Bishopsgate. Quite a few of the protesters are wearing masks, the atmosphere is febrile there's a lot of anger. While the police look anxious, they're not yet in riot gear. There are a lot of media.

11am, Liverpool Street Station. The Green Horse marchers wouldn't win any prizes for numbers, but for sheer style the hundred-plus marchers gathered on Bishopsgate prove that British elan and individuality are alive and well. There are bowler-hatted zombies, rhino-suited cyclists and Chinese dragon style dinosaurs spilling good-naturedly into the road. There are still more media than protestors, and more police than both, but the atmosphere is carnival-esque for the time being.

9.40 am, Bishopsgate. The City of London is humming with expectation as police and protestors make final preparations. Trainloads of dressed-down commuters have spilled out onto the streets at the Square Mile's stations to be met by a massive police and security presence but few obvious protestors. I pop down to the Bank of England where my group will be heading later this morning and find a media scrum is in full effect, cameramen sighting their best angles, reporters chatting up friendly policemen. Just around the corner, I encounter a column of fully armoured mounted riot police. The countdown begins.