Jeremy Corbyn has urged activists protesting at the Conservative Party conference to refrain from "personal attacks".
The Labour leader will head to Manchester, where the Tories are gathering, to take part in a rally as part of a campaign to protect postal services.
A series of demonstrations and protest events are planned, backed by unions and other campaign groups, while the Conservative conference takes place.
Party leaders have traditionally stayed away from their rivals' conferences, but Mr Corbyn will address a public meeting organised by the Communication Workers' Union on Monday in Manchester.
In a message on Twitter, Mr Corbyn said: "Ahead of Tory Conference I urge all activists to focus on policy & to take no part in personal attacks."
A flash mob at Manchester Piccadilly railway station featured protesters waving placards reading "Tories not welcome, go home" and a knitted banner reading "don't stitch us up".
A protest camp, which featured an all night rave attended by around 200 people, was set up in Piccadilly Gardens in the city centre, leading to "numerous complaints from residents and local businesses about noise levels", police said.
"Shortly after 9pm on Friday night, a music system and protest camp was set up in Piccadilly Gardens. The protests are against the Government's anti-austerity measures and timed to coincide with the Conservative Party conference taking place in Manchester between Sunday and Wednesday," Inspector Phil Spurgeon of Greater Manchester Police said.
Ahead of the conference, Tory party chairman Lord Feldman emailed members suggesting that they should not wear their passes outside the ring of steel surrounding the Manchester Central complex.
He said there was a protest march planned by the TUC on Sunday, adding: "It will be particularly important not to wear your Conference security passes outside the secure zone."