Scotland Yard's new plans to control crowds during mass protests have not yet been trialled it emerged, as thousands of protesters prepare to descend on central London this weekend.
More than 100,000 people are expected to join the rally on Saturday against cuts in public spending. More than 650 coaches have been hired and 10 trains chartered from as far afield as Scotland.
Police are set to appoint a "containment manager", in charge of the controversial kettling tactic, to monitor the rally. Scotland Yard says it has received "early intelligence" about protesters seeking to disrupt the march.
Metropolitan Police officers are planning to avoid a repeat of the violence that marred student protests last year, and led to the attack on the royal car, containing Prince Charles and the Duchess of Cornwall.
But Assistant Commissioner Lynne Owens said the new tactic had not yet been tested because the two previous protests for which it was in place had been peaceful. "One of the issues with containment has been that sometimes it has gone on longer than we would think necessary in the future, on the basis that we wanted to arrest some people.
"We are trying to speed up the process so that those who have not been engaged in criminal activity can leave very quickly."
The role of the "containment manager", who will have a team of officers reporting to him, is to monitor the rally for potential trouble spots, and decide where and when to contain protesters. It is designed to avoid the more ad-hoc approaches that have led to increased criticism of the Metropolitan Police since kettling was first used during the G20 protests of April 2009.
Ms Owens said: "From the moment the protest starts, that person is watching the route and is planning, if there has to be a containment, where it would most safely be.
"He will be able to have a conversation directly with the officers who are on the containment and ensure that the messages get to our staff, which is also a challenge to us in big noisy events, at the same time as it gets to the protesters who may choose to leave the area."
TUC organisers plan to provide up to 2,500 stewards along the route, including up to 350 senior stewards who will act as negotiators. They will also work with police commanders, who will tackle any more serious incidents of violence.
The social media site Twitter has also been drafted in to improve communications before and during the march. Updates will be available by mobile.Reuse content