For this protest, called by the Stop the War Coalition with only a couple of days’ notice, police had cordoned off the southbound carriageway of Whitehall, and StWC had set up a small stage in front of Downing Street. Similar gatherings were taking place, we were told, in 30 towns and cities across the UK.

The protest, called for midday, continued to grow over the next couple of hours as a variety of speakers took the stage, and I’d estimate at least 2,000 attended in all.

After John Rees spoke for the coalition, the first big celeb speaker, dressed in a very pricey-looking grey winter coat, was Brian Eno, who spoke from the heart about the illogicality of a military “solution”.

After a typically rousing effort from Owen Jones, we heard from Green deputy, Dr. Shahrar Ali, and then Sabby Dahlu from ‘Stand Up Against Racism’, who spoke passionately about the right-wing media demonisation of Muslims, and the resulting rise in racist attacks.

A heartfelt and honest speech from the massively talented actor Mark Rylance, was followed by well-honed oration from George Galloway.

Next on was Tariq Ali, who used to write regularly in the Guardian, but, in talking about the media frenzy over Corbyn, Paris, and a Syria attack, admitted he can no longer bear to read it. His speech reminded us of the long-standing plan, exposed many years ago by ex-NATO supreme commander, General Wesley Clark, to “take out” a series of countries in the Middle East, including Syria. This story was backed up recently by the revelation from French Foreign Affairs minister, Roland Dumas, that UK officials confessed to “preparing something”, an organised invasion of rebels into Syria, more than two years ago.

By 1.30, with the south carriageway pen full to overflowing, police had given up trying to persuade protesters outside Downing Street to move over the road, and with the pavement full there too, some folk decided to invade the north carriageway and completely block the road.

Sergeant Dearden is often seen at protests carrying out surveillance in his National Domestic Extremist Unit role, but on this occasion he was in charge of police operations and wearing Inspector epaulettes. After sending in some Police Liaison Officers to gather intelligence and try persuasion, he then brought in some TSG officers to push people off the road and allow some traffic through.

However, demonstrators were persistent, and staged a sit-down, at which point, police closed off the carriageway at Parliament Square, where they listened to the final speaker, Dianne Abbott, who had been delayed travelling, as she brought greetings of solidarity from the Labour leadership.

As the protest pen cleared, and traffic began to pass south, a little after 2.30, people began to drift away from the sit-down, and cleared the road by about 2.45.

There is another protest planned at Parliament for 6pm on Tuesday IF the government announces a vote to take place on Wednesday. Check stopwar.org.uk for new information on this.

UPDATE – announcement HAS been made, so Wednesday debate, and emergency protest at Parliament 6pm Tuesday 1st August