Black Lives Matter protesters sparked traffic chaos after blocking a major road into Heathrow as part of a day of nationwide action that saw a number of activists arrests.
Activists in London, Birmingham, Manchester and Nottingham took part in a "nationwide shutdown" to call for greater awareness of discrimination against black and minority ethnic communities following a spate of shootings in the US.
The protests were scheduled to mark the five year anniversary of the death of British father Mark Duggan, a 29-year-old black man who was shot by police as he stepped out of a minicab in Tottenham. He was not holding a handgun at the time, and his death is regarded as one cause of the riots which raged across London and English cities throughout the summer of 2011.
The Black Lives Matter group, which has sprung up in response to similar incidents in the US, calls itself a "worldwide protest movement" according to its social media pages and has its roots in the US.
One of the most high-profile demonstrations by British activists on 5 August took place by Heathrow Airport on the motorway towards Terminals 1 and 2. At least 10 protesters chained themselves to tarmac with a large banner.
But thousands of protesters marched at an event in Manchester in a peaceful demonstration comprised of all ages and colours, although mostly young and black.
The banner at the Heathrow demonstration had the words "This is a crisis" painted across it. Many of the protesters on the tarmac had their arms chained together.
Police moved in to arrest 10 protesters at the Heathrow site, Met Police confirmed with The Independent. They said police were called out to the area at 8.25am on 5 August and traffic congestion had become a problem.
Black Lives Matter activist Adam Elliott Cooper, who is a 29-year-old from London, said the location was appropriate because "many people are either being killed at our borders or being sent back to certain death".
Four more protesters, also part of Black Lives Matter, have similarly been arrested in Nottingham after they lay down in the path of a tram and halted public transport in the city centre.
Further protests took place in Birmingham, with protesters holding cardboard signs saying #BlackLivesMatter and standing on a dual carriageway.
And up to 3,000 people attended a Black Lives solidarity march in Manchester, in an event which reportedly involved no clashes with the police.
US activists and their public supporters have expressed outrage and fear at shootings of unarmed black citizens in the US in recent months.
Last month, a black carer called Charles Kinsey who was trying to protect his autistic patient was shot by a policeman in Miami, Florida – and when the police officer was asked why he had done so, he reportedly replied "I don't know".
The British group said it wanted to commemorate the fifth anniversary of Mark Duggan's death.
"We stand in solidarity with the families and friends of all who have died at the hands of the British state. We take action because justice has not been delivered through conventional means: the police, the IPCC, the courts or the legislature," it said.
The group said it aims to highlight "the struggle for Black Lives in the UK and #Shutdown state-sanctioned racialised sexism, Islamophobia, classism, ableism, homophobia and transphobia", adding: "We fight for liberation."