Demonstrations are taking place across the UK against Boris Johnson's decision to suspend Parliament in the run-up to Brexit.
Thousands of protesters have taken to the streets in cities including Manchester, Leeds, York and Belfast.
Parts of central London were brought to a standstill, with people chanting: "Boris Johnson, shame on you".
A small group of counter-protesters, marching in support of the prime minister, also arrived in Westminster.
Mr Johnson's plan to prorogue Parliament prompted an angry backlash from MPs and opponents of a no-deal Brexit when he announced it on Wednesday.
If the prorogation happens as expected, it will see Parliament closed for 23 working days.
Critics view the length and timing of the suspension - coming just weeks before the Brexit deadline on 31 October - as controversial.
Protests are taking place in more than 30 towns and cities across the UK, including Edinburgh, Belfast, Cambridge, Exeter, Nottingham, Liverpool, Manchester and Birmingham.
In London, demonstrators stopped traffic in Whitehall and the West End.
They also staged a sit-down protest in the roads around Trafalgar Square, before marching to Buckingham Palace shouting: "Whose democracy? Our democracy."
Speaking at a rally in Glasgow, Labour leader Jeremy Corbyn said the protesters' message to the prime minister was: "No way do you take us out without a deal".
"Demonstrations are taking place everywhere because people are angered and outraged about what is happening," he added.
In Oxford, crowds holding banners gathered outside Balliol College, where Mr Johnson studied at university.
Named "Stop the Coup", the protests are organised by anti-Brexit campaign group Another Europe is Possible.
The group also said there were protests planned in Amsterdam, Berlin and the Latvian capital Riga.
Shadow chancellor John McDonnell and shadow home secretary Diane Abbott both addressed crowds in London.
Speaking from a stage near Downing Street, Ms Abbott told protesters: "We cannot allow Boris Johnson to shut down Parliament and to shut down the voice of ordinary British people."
Chancellor Sajid Javid, speaking on BBC Radio 4's Today programme, defended the prime minister's decision to suspend Parliament.
He said: "It's quite usual this time of year for Parliament to go in to a recess. It's perfectly correct and appropriate to prorogue Parliament.
Meanwhile, a petition against the prime minister's plan to suspend Parliament has received more than a million signatures.
And on Friday, former Tory Prime Minister Sir John Major announced he will join forces with anti-Brexit campaigner Gina Miller to oppose the decision to suspend Parliament in the courts.
He believes Mr Johnson's move to suspend Parliament is aimed at preventing MPs from opposing a no-deal Brexit.
The prime minister has dismissed suggestions that suspending Parliament is motivated by a desire to force through a no deal, calling them "completely untrue".
Foreign Secretary Dominic Raab said: "The idea this is some kind of constitutional outrage is nonsense."
BBC
BDST: 1004 HRS, AUG 31, 2019
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