|'Kettling' is a well-known tactic which has been used by UK police in the past [EPA]
"Kettling" - a tactic being used by British police to fence-in and tire-out protesters at the London G20 summit - is sparking its own wave of protest.
The method is aimed at defusing tension and thereby [in theory] reducing the potential for demonstrations to become violent, police sources argue.
I was among the many journalists kept inside this police ring, established and eventually tightened as the afternoon wore on.
Our press cards gave us the freedom to leave, but that would have meant we couldn't return to continue reporting on the event.
For the protesters, the police strategy meant that they were being held against their will.
Click on the video icon to see what happened when our team got stuck in the middle of a "kettled" crowd.
The vast majority of those demonstrating on Wednesday were peaceful.
Indeed, for most of the day the mood was festive, rather than furious.
People were playing music and dancing, while others were juggling.
There were some sporadic outbursts of violence, notably attacks on the Royal Bank of Scotland branch on Threadneedle Street, but otherwise the masses remained relatively calm.
It was only as the afternoon dragged on into early evening that the agitation started to increase.
The crowds had been there all day, many without anything to eat or drink.
The warm spring day had turned into a cold afternoon and it seemed that many just wanted to go home.
Most expected they would be allowed to go fairly soon, but the delivery of a set of portable toilets perhaps gave us a clue as to what the police had planned.
Kettling is a well-known tactic, which has been used in the past.
London police used it against May Day protests around Oxford Circus in 2001.
When separate protests moved in from different parts of London on Wednesday, converging outside the Bank of England, the "kettle" was once again implemented.
Teams of police, including a riot squad, pushed into every street and lane, blocking demonstrators and locking them into a small area at the heart of London's financial district.
By early evening, the tension had mounted and people began hurling objects at the police lines.
A life-sized doll dressed as a bank executive was set on fire and barricades were moved and shunted.
The police responded by pushing back, often with more force than the protesters had initiated.
|The police often used 'more force than the protesters had initiated' [GALLO/GETTY]
Some demonstrators and police were injured.
One protester we interviewed dressed in a dark green jacket, with blood pouring from his left eye, said: "I was only beaten because I was trying to get out".
The crowd erupted in chorus, demanding: "Let us go, let us go!".
The tactic has caused enormous controversy. Many have asked if police should be keeping people against their will?
Duncan Campbell, writing about "kettling" in the Guardian, a British newspaper, says "what is significant about its use ... is that it is now apparently being applied in a rigid, inflexible way - policing as video-game".
So, was it the right thing to do? What is your view? Join the debate.