When 23 Russian diplomats and their families were expelled from the UK following the nerve agent attack on Sergei Skripal and his daughter Yulia, their flight home departed not from Britain's biggest airport at Heathrow but from Stansted in Essex, an airport usually associated with budget airlines and city break destinations rather than international diplomacy and espionage.
In fact, the former military air base is often used for high-security arrivals and departures and in case of reported security alerts such as hijacks or bomb scares.
In October 21017, a security-enforced redirection of a Luton-bound Ryanair flight from Lithuania to a new destination at Stansted Airport was another case of Britain's third largest airport being called into emergency action.
Fortunately nothing suspicious was found, and other than upsetting the flight schedules, no damage was done. But why is it always Stansted that ends up being used in this situation?
Situated 37 miles outside London and 20 miles from Chelmsford in Essex, Stansted airfield was used by the RAF and US Air Force during World War II, after which it came under the control of the Ministry of Civil Aviation.
It is Britain's officially designated airport dealing with hijacks because the layout of the facility allows planes to stand well away from terminal buildings and other planes in a situation where negotiations may be required.
Staff undergo regular security drills, and there are specialist security staff for the hijack scenario.
The first time Stansted's emergency function was called into action was in 1975.
A British Airways flight from Manchester to Heathrow was hijacked and after passengers were allowed off at Heathrow because the hijacker believed he would be allowed to fly on to Paris, the plane was diverted to Stansted and he was arrested in possession of a toy pistol and imitation dynamite.
Seven years later, in 1982, an Air Tanzania Boeing 737 internal flight carrying 99 passengers ended up at Stansted after previous stops in Nairobi, Jeddah in Saudi Arabia and Athens.
After 26 hours of negotiations, the hijackers surrendered and their passengers were released unharmed.
Another high-profile incident occured in August 1996, when six Iraqi nationals took control of a Sudanese A130 Airbus flight between Khartoum and Amman, with 197 passengers and crew on board.
Armed police were deployed, with the SAS on call to help them if needed, before successful negotiations saw the passengers and crew released (below).
The hijackers, who claimed to have TNT explosive and were carrying sauce bottles disguised as grenades, said they were seeking refuge from the regime of Iraqi dictator Saddam Hussein.
They were given jail terms of five to nine years before later being cleared and freed by the Court of Appeal.
In Feburary 2000, Stansted played host to Britain's longest airport siege, when nine Afghan men held 156 passengers and crew on a hijacked Afghan Ariana internal flight hostage for three days.
The group, who were opponents of the country's Taliban regime, were jailed for up to five years before having the convictions quashed.
There were also two incidents in 2013 - a Pakistan International Airlines flight from Lahore to Manchester was diverted to Stansted and escorted by RAF Typhoons due to an unspecified onboard threat, and in September of the same year Sri Lankan Airlines flight from Colombo to Heathrow was diverted after a passenger claimed 'something' was in the luggage hold.
Following the emergency landing, a 49-year-old man was arrested and jailed for three years after admitting a charge of endangering an aircraft.
Earlier in February 2017, a Pakistan International Airlines plane on its way from Lahore to Heathrow was escorted by Typhoon jets in Stansted after an anonymous phone call issued a security warning - which turned out to be fake.
It isn't just security threats that fly into Stansted either. After security concerns over a visit by US President George W. Bush to the UK in June 2008 led to severe disruptions to commercial services at Heathrow Airport - the airborne entourage included a 747, a 757 and four helicopters as well as Air Force One - leading airlines petitioned the authorities that it should never happen again.
As a result Barack Obama's three visits to London in 2009, 2011 and 2016 all arrived and departed the UK through Stansted instead, as did a visit by First Lady Michelle Obama and their daughters Malia and Sasha in 2015.
In the image below, the President's helicopter, Marine One, can be seen flying over the airport.