The protestors, who are said to be noisy but peaceful, are part of a day of anti-capitalist action taking place today.
About 400 police are keeping the protestors hemmed in outside the Euston office while they extract individuals for body searches.
The protestors are banging drums and chanting ‘let us out’.
Police are also contending with a huge number of press and photographers who had gathered at the Grant Thornton building to watch the protests.
Earlier today the protest began in the City when cyclists gathered outside Liverpool Street Station where they began a mass rush-hour ride in protest against the car culture.
They progressed to Kings Cross station where activists handed out free ‘veggie’ burgers outside fast food chain McDonalds. Between 600 and 700 people brought Euston Road to a standstill. Under police escort, the group then moved towards Euston station and the offices of Railtrack.
Around 20 protestors have now moved on to Oxford Street where they are staging a sit down protest.
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