FREE now SUBSCRIBE Invalid email Make the most of your money by signing up to our newsletter fornow We will use your email address only for sending you newsletters. Please see our Privacy Notice for details of your data protection rights.

Two people were hospitalised and 26 others treated by the London Ambulance Service following a "chemical incident" at the busy central airport, after the terminal building was evacuated when some passengers reported feeling unwell. Around 500 passengers and crew members were forced to wait on the tarmac after fleeing the busy central London airport when a fire alarm sounded just before 16.15pm. Police and firefighters investigating the incident, which saw passengers treated for breathing difficulties, have now discovered what is "believed to be a CS gas spray", more commonly known as tear gas, a spokesman said. The airport spokesman said it was unclear what had caused the chemical incident, which is not beleived to have been a terrorist act, but officers were "investigating whether it was the result of an accidental discharge of the spray". The airport has now been declared safe, with the London Fire Brigade and Metropolitan Police jointly carrying out two complete sweeps of the the building, during which no elevated readings were found, although passengers say they have been told they won't be flying tonight.

TWITTER Emergency Services attend London City Airport over fears of a

Speaking to the Express, Alistair Snowie, 21, told of how everybody ran out the building in panic before an alarm even sounded. He said: "All of a sudden, everyone started coughing at the same time. Everyone was aware something was wrong, and everybody ran out of the building. "No alarm went off, but everybody was struggling to breathe and it was really quite scary." Mr Snowie, who was supposed to be flying to his hometown of Edinburgh earlier this evening, added that "by that point [that the fire alarm sounded], everyone had already ran off." Adding that passengers were still outside the airport, where they had been for over three hours, he said: "they still haven't told us what it is, we don't know anything."

Twitter British Boxer David Haye tweeted from the airport, claiming people were struggling to breathe

British professional boxer David Haye, who was at the airport waiting for a flight to Scotland, reported that "everybody started coughing uncontrollably". In an interview with the BBC, Chris Daly, 35, from Southend, said he had just landed at the airport after travelling on a British Airways flight from Glasgow when he heard the fire alarms. He said: "When we got into the airport terminal building we could hear the fire alarms going on, then there were announcements in three different languages saying this is a fire alarm and the crew were directing us at the baggage carousel to evacuate the building.

Twitter Emergency Services remain at London CIty Airport

"We are now all standing on the tarmac under the wing of the airplane because it has started to rain. "I can see some plane circling in the sky but nothing else has landed. No-one has really told us anything. We saw some fire crew going inside to do a sweep. "I saw something on Twitter about it being a possible chemical incident. I'm not particularly worried because we are outside now."

Instagram Ambulance crews treated 26 passengers at London City Airport

The emergency services were quick to attend the scene, with London Fire Brigade confirming they had three fire engines at site, in addition to amulance crews, police and a Hazardous Area Response Team. London Ambulance Service tweeted: "Ambulance crews and our Hazardous Area Response Team are attending the incident at London City Airport. More information to follow." While London Fire Briagde also took to social media to confirm they were attending the evacuation, writing: "Firefghters are investigating the incident at London City Airport. We have 3 fire engines and 15 fire fighters at the scene."

TWITTER Passengers waiting on the tarmac outside London City Airport

Passengers have now been waiting outside the terminal for almost three hours, although reports suggest they are starting to be allowed back into the building, despite not being given any information as to what the suspected "chemical incident" was. Many are claiming the atmosphere at the airport is calm, despite travellers not being given much information as to what the suspected "chemical incident" was. One passenger, Shauna Bull, told the BBC she was not "overly worried". She said: "They've separated us into domestic and international and I thought we were going to get to go home but they've taken us into a room for border force control to process us. "There are buses now taking people on toilet trips to a toilet somewhere so I think we could be here for a while yet. No-one is saying anything. "I've told my dad, who I was supposed to be meeting, and he's sitting in a pub now telling his mates. "I'm not overly worried. I just hope they sort it out. I live in London so I'm used to this sort of thing."

Instagram Emergency services at London City Airport

Reports from the scene suggested initial confusion amongst crowds. One Twitter user posted: "London City Airport's on fire apparently. All evacuated to the tarmac". Whle another wrote: "There is a fire alarm at London City Airport. I can only hope it's a false alarm as the staff are ambling around aimlessly". Twitter user Mark Rae confirmed other emergency services had also attended the alert. He said: "London City airport in lockdown, terminal evacuated, police, fire and ambulance all here."

London City Airport evacuated as 'chemical incident' leaves passengers feeling sick Fri, October 21, 2016 Hundreds of passengers and crew members were forced to wait on the tarmac after fleeing the busy Central London airport when a fire alarm sounded due to a "chemical incident''. Play slideshow Twitter 1 of 12 Hundreds of passengers and crew members were forced to wait on the tarmac after fleeing the busy central London airport when a fire alarm sounded due to a

TWITTER Passengers waiting outside London CIty Airport

A spokesperson for for London City Airport confirmed the evacuation but could not give a cause. Speaking to the Express, he said: "The fire alarm activated just after 4pm, it was a routine procedure evacuation and the airport terminal building remains evacuated whilst fire services investigate the cause." He was unable to give any further information as to the cause at this time. However, the airport released a statement through a series of Tweets, confirming the discovery of CS gas. The statement said: “We apologise to passengers for inconvenience caused today when an alarm was activated, triggering a full evacuation of the airport terminal. “Passengers were evacuated safely & we thank them for their patience. Following the evacuation, some individuals reported feeling unwell and were treated at the scene by London Ambulance Service. “Emergency services responded to evacuation, citing a possible chemical incident with firefighters & police officers jointly conducted sweeps of the airport building. The search of the airport led to the discovery of what is believed to be a CS gas spray. “Whilst the cause of the incident has yet to be confirmed, officers are investigating whether it was the result of an accidental discharge of the spray. "The airport was declared safe and reopened at approximately 1900.”

GETTY Yesterday the Jubilee Line was closed after a "suspect item" was found at North Greenwich station