It is the latest demonstration involving the anti-racism activists, who brought traffic to a standstill outside Heathrow Airport - and carried out similar protests in cities around the country - in a co-ordinated day of action last month. 

The campaigners, whose international movement was set up following the killing of black teenager Trayvon Martin in Florida four years ago, said Tuesday's action was taken "in order to highlight the UK's environmental impact on the lives of black people locally and globally". 

Image source, Aimee Roweth

Image source, Aimee Roweth

In a statement, the protest group's UK division cited expansion plans at the airport as the cause of their action. 

It said: "Recently London City Airport was given approval to expand its capacity, a move that consigns the local community in Newham to further deterioration of their environment. 

"The average salary of a London City Airport user is 136,000 euros (£114,000) and 63% of them work in business, finance or other business services. It is an airport designed for the wealthy. 

"At the same time 40% of Newham's population struggle to survive on £20,000 or less. When black people in Britain are 28% more likely to be exposed to air pollution than their white counterparts, we know that environmental inequality is a racist crisis." 

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The Metropolitan Police are investigating how the protesters managed to get air-side - including the suggestion that they swam across the Thames to gain access to the site, before locking themselves together on the runway. 

A Met spokesman said: "We were called at around 5.40am to reports of a number of protesters who made their way air-side. 

 "There are currently nine protesters on the runway at the airport. They have erected a tripod and have locked themselves together. 

 "Officers are currently on scene and are negotiating with them. We are awaiting the arrival of specialist resources that are able to unlock the protesters. 

 "No arrests have been made at this stage."

A London City Airport spokesperson added: "The runway is currently closed due to protesters on site.

"We apologise to passengers for any inconvenience to their journey."

City Airport is popular with bankers and business professionals due to its proximity to Canary Wharf in London Docklands.

Last year, a record 4.3 million passengers used the airport.

The campaign group Black Lives Matter has claimed it is behind the demonstration at London City Airport that has disrupted a number of flights after protesters gained access to the runway.

BBC Travel

Some 20 bus routes across East, west and central London are severely disrupted because of a strike. There’s no service on routes 31, 328 & RV1.

The A40 is slow coming in to town from Hillingdon to Gypsy Corner at Acton after   a couple of issues earlier this morning and the A406 is slow southbound from Barking to Beckton because of faulty traffic lights.

For the latest information go to our travel page or follow us on Twitter @BBCTravelAlert, external

It's a cloudy start to the day with mist and fog patches at first, but these should gradually clear. 

Some bright or sunny spells will develop through this afternoon and it will feel very warm and humid, particularly in the sunshine. 

Top temperature: 24C (75F). 

We'll be bringing you updates of all the latest news, sport, travel and weather in London until 18:00.

If you would like to get in touch, you can tweet, external, email or leave a message on our Facebook, external page.

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BBC London News

Join us again from 08:00 on Tuesday for more news, sport, travel and weather updates but keep an eye out here for updates throughout the evening.

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