Brass bands and banners, then it turned nasty

But just before 1pm, at the junction of Threadneedle Street and Bartholomew Lane, near to the Bank of England, it turned ugly.

Angry protesters tried to force their way through police lines. They hurled empty beer cans, fruit and flour at officers from the City of London and British Transport Police.

Officers were forced to draw batons, lashing out at surging groups of protesters attempting to reach a camp established by climate change activists in nearby Bishopsgate.

Demonstrators holding horses' heads made of cloth and sticks, flags and figures of death repeatedly clashed with the officers in a tense stand-off.

But earlier, however, as police helicopters hovered overhead, a brass band struck up Down By The Riverside, while youths blew whistles.

One group waved red flags, emblazoned with the word "Revolution", while another huddled under a banner declaring "Make Love Not Leverage".

Two City workers, wearing suits, surveyed the crowds around them. "We must be the two biggest idiots in London right now," declared Graham Heffernan, an office manager, seeing the mob was not turning nasty.

Most of the City had dressed down today, heeding the warnings of their bosses. But not hard to spot, however, were many wearing chinos and polo shirts.