It's all systems go at Heathrow's in-house Covid-19 testing centre, as service manager Joel and staff deal with an increasing amount of passengers needing their assistance. Meanwhile inside Terminal 2, the cleaning team are on the hunt for a special kind of vagrant which requires some very hi-tech infrared equipment.

Passenger experience manager Numan is back after a year on furlough and faced with a terminal of 24 passengers who are missing 50 pieces of luggage - and it's his job to find them. Out on the airfield, Inspector Shard and Sergeant Dawson receive word of a man who is wandering around on the apron, sparking a cross-terminal manhunt.

Terminal 3 re-opens its doors to the public 15 months into the global pandemic, with 11 Virgin flights set to take off, but teething problems threaten to delay one of the departures. It's business as usual in Terminal 5 as Passenger Experience Manager Tas is called to deal with an arriving passenger who is refusing to pay for his mandatory Covid tests, while the City of London Corporation's Animal Reception Centre have quarantined two dogs who have flown into the USA without proof of treatment for tapeworm.

Staff at Heathrow prepare for the arrival of Air Force 1, and although the airport is quieter than usual, it is still a huge effort logistically to make sure things run smoothly. Meanwhile, security officer Estafania scrutinises the contents of passengers' hand luggage, as well as their face masks, and airside officer Ian has his hands full.

An inbound passenger has an entourage of armed police officers waiting for him, while a propeller plane arrives from the Isle of Man. Demi plunges into his favourite role of `passenger saviour" when 12 young divers are struggling to make their championship flight.

With the new regulations for travel becoming ever more complicated, it's not surprising passengers are starting to fight back.

The Aviation police in the form of Sergeant Dawson and Inspector Shard have their diplomatic hats on as they uphold the new quarantine laws of the land. Since February 15th anyone travelling back from a red-list coronavirus hotspot must stay in a special quarantine hotel for 10 days. But in tonight's episode, one passenger who has changed planes in a red country  is adamantly refusing to comply with the rules - and it's not just human passengers who are forced to have a stopover.

The City of London Corporation Animal Reception Centre handles tens of millions of animals who pass through Heathrow every year and whilst staff adore the delightful dog reunions, there are some tardy tortoises who end up having to hang around.  

This episode goes behind the scenes of travel's new normal - the test and trace. Passenger numbers may be down by 77%, but deciphering the protocols of all 206 countries that Heathrow fly to is more complicated than navigating Spaghetti Junction in rush hour.

On the frontline is Joel, the manager of Heathrow's testing centre, who leads the charge in trying to reduce passenger stress and makes sure that everyone gets the right test for the right country –  tonight he's dealing with a particularly irate Israeli family. 

Outside on the airfield, we're back with the airport's favourite moustache wearer – Airside Ian, who has a new weapon to test out on the ever-encroaching wildlife. Things are heating up in immigration, where Passenger Experience Manager Suki has an emergency on his hands, and Security Officer Estefania gets an unexpected make-over.

Britain is on the cusp of holiday season and the staff at Heathrow are revving up for passengers from all over the globe. Today cameras meet a new member of the Passenger Experience Manager Team, Suki. It's the busiest day in May and with an increase in passengers, his Terminal 2 forecourt is getting busy with holidaymakers returning to the airport after months of having to stay away. One car has outstayed its welcome in the drop-off zone, and Suki has to take drastic action. And a passenger passing through the airport onto a connecting flight causes a security breach when they lose their phone between departures and arrivals.

Dame Julie Walters narrates as, while COVID travel restrictions begin to ease, cameras continue to explore behind the scenes at the massive transport hub, giving audiences an exclusive look at how one of the world's most popular airports handles a worldwide pandemic.

Filmed over the last 18 months, with passengers trickling back into an airport dealing with new and ever-changing challenges, it's still business as usual at Britain's busiest airport.

The discovery of a new variant of Covid-19 causes chaos in Heathrow as airports around the world begin to close their borders to the UK. As flights are cancelled before the passengers' eyes, they scramble to get on any available plane in a desperate attempt to get home.

Flying for the last time out of Heathrow tonight is the iconic Boeing 747, with plane spotters around the world hoping to bid it a fond farewell.

Inside the terminal, it's hello to some new rather robotic members of staff, and outside on the airfield, new cargo driver Dylan is hoping his hankering for hypnosis can get him out of a jam.

It's Lockdown, but that doesn't stop Heathrow: Britain's Busiest Airport flying in for a new series.

With only one runway and two terminals open, Heathrow's depleted staff are fighting to keep business going. At the helm is King of Customer Service Demi, dishing out help to all those allowed to travel, including tracking down a missing passenger. Plus, the situation means that nasal swabbing replaces duty free, which could save one couple's nuptials.