Climate change activists on Thursday brought parts of the British capital to a standstill in a fourth consecutive day of demonstrations that have so far led to more than 400 arrests.
Hundreds of protesters continued to rally at several spots in central London, where they have blocked a bridge and major road junctions this week as part of a Europe-wide civil disobedience campaign over the issue.
The Metropolitan Police said, as of 0830 GMT on Thursday, that 428 people had been arrested since the protests began on Monday, with reports of further detentions during the day.
Meanwhile, a judge denied bail to three people who appeared in court charged with obstructing the transport system at financial hub Canary Wharf on Wednesday.
District judge Julia Newton ordered the trio, who allegedly glued themselves to a train, be held in custody until their next court appearance on May 16.
Under pressure in the media to crackdown on the distruptive demonstrations, interior minister Sajid Javid warned "unlawful behaviour will not be tolerated" after meeting Met Commissioner Cressida Dick.
"No one should be allowed to break the law without consequence," he said in a statement, adding he expected police "to take a firm stance".
Protesters have been snaring traffic and setting up impromptu encampments at Waterloo Bridge, Parliament Square and at Oxford Circus in London's busy West End entertainment and shopping district.
They laid trees in pots along the bridge's length and also set up camps in Hyde Park in preparation for further demonstrations.
More than 1,000 officers were being deployed to the streets of the capital each day this week, according to the interior ministry.
The police have ordered the protesters to confine themselves to a zone within Marble Arch, a space at the junction of the park, Oxford Street and luxury hotel-lined Park Lane.
The protests are being spearheaded by the "Extinction Rebellion" activist group, which was established last year in Britain by academics and has become one of the world's fastest-growing environmental movements.
It has vowed to maintain the protests for weeks in a bid to force state action over climate change, with Heathrow Airport -- Europe's busiest flight hub -- the latest site to be targeted on Friday.
The group wants the British government to declare a climate and ecological emergency, reduce greenhouse gas emissions to zero by 2025, halt biodiversity loss and be led by new "citizens' assemblies on climate and ecological justice".
Its protesters say they are practising non-violent civil disobedience and aim to get arrested to raise awareness of their cause.
The majority arrested this week were detained for breaching public order laws and obstructing a highway.
However, police seized three men and two women outside the UK offices of energy giant Royal Dutch Shell on suspicion of criminal damage after they allegedly daubed graffiti and smashed a window there.
London, United Kingdom | AFP