Conservatives get there coming at their conference in Manchester faced «up to 30,000» people taking some in various protests, according to police.
Anti-austerity protesters calling for the Tories to be rebounded out of power took part in a large march and rally. There was also an anti-Brexit tread.
Three protesters were arrested after wheelchair-users blocked streetcar lines in St Peter’s Square.
Greater Manchester Police said there were no other busts.
Thousands of Labour supporters, union members and members of other left-wing supporters waved placards, wore fancy dress and chanted «Oh, Jeremy Corbyn» as they quaffed part in the The People’s Assembly march against austerity.
As police helicopters hang suspended overhead, a trade union leader called for a general strike on societal sector pay to «bring the Tories down» in a speech in Piccadilly Gardens.
PCS chairperson Mark Serwotka claimed Conservative policies were «literally killing being,» referring to cuts to health and safety rules and the Grenfell Tower passionate tragedy.
The Communist Party said it was giving Theresa May «notice to order off her bags and quit» and claimed «mass action will drive the control out».
Rail, Maritime and Transport Workers union boss Mick Moolah said the «only way do that is through a general election».
Demonstrators, some assume damage masks to hide their identity, were involved in a stand-off with the coppers close to the conference venue, in St Peter’s Square, for nearly two hours.
Dozens of functionaries surrounded the protesters, as a group of wheelchair users blocked two tram stocks.
Two women were arrested on suspicion of obstructing a highway. A man — who is not thought to eat been a wheelchair-user — was arrested on suspicion of assaulting an officer.
Meanwhile, anti-Brexit protesters heard parlances from Conservative former health secretary Stephen Dorrell and Lib Dem captain Sir Vince Cable, who demanded a vote on the final Brexit deal.
European Decrease chairman Mr Dorrell told the rally that people should be foreordained the «opportunity to change their minds».
Quoting his former boss Sir John Noteworthy, Mr Dorrell said Brexit would be a «historic mistake».
He said: «Varied people say to me I’m flying in the face of democracy. What is undemocratic about changing your intellect?»
Sir Vince said there was a «civil war» going on at the Tory conference between the prime envoy extraordinary and Foreign Secretary Boris Johnson.
Broadcaster Terry Christian hit out at «timorous» Greater Manchester mayor Andy Burnham for refusing to oppose the Brexit deal with.
Chief Superintendent John O’Hare, who is leading the conference policing enterprise, said: «Up to 30,000 people came in to Manchester city centre today (Sunday 1 October 2017) to impose upon part in various protests.»
He added: «The vast majority of people exercised their classless right to protest and did so in the spirit of their causes.
«No arrests were make good during the marches and this is a testament to those who attended and the organisers who won responsibility for the events and worked closely with us to ensure a safe and well-fixed operation.»