It was loading a shipping container full of aid for Europe’s stricken migrants that gave Tess Berry-Hart the idea for her next play.

It was loading a shipping container full of aid for Europe’s stricken migrants that gave Tess Berry-Hart the idea for her next play.

Aware that many refugees make the perilous journey to the continent in these huge metal crates, she wondered what forced people to make that leap into the unknown - and how difficult the voyage must be.

Arcola audiences will get a sense of the claustrophobic crossing in Berry-Hart’s immersive thriller Cargo.

Entering the auditorium through metal container doors they will sit on pallets and sandbags surrounded by boxes, with the action happening around them.

“I was sorting out aid and taking it to Calais and Samos,” says the mum-of-two who as co-founder of grassroots giving group Calais Action has sent tonnes of aid to Europe’s migrant camps.

“Standing in a shipping container, I thought ‘how desperate would you have to be to get into one of these?’

“I decided to set the play with the audience in a container for the length of time it takes to cross a border.

“Where everyone is travelling to Europe as it were.”

False walls contract the space, lighting is minimal, as against a soundscape of thrumming engines and metallic clangs, a band of strangers fleeing a country racked by civil law wrestle with conflicted loyalties and betrayal.

Two find themselves on opposing sides of the war, at least one is an unaccompanied minor.

Over the last two years, Berry-Hart has witnessed the plight of many migrants on trips to France and Greece.

“When I started writing this two years ago, I was just getting interested in the refugee question and how I could help, I couldn’t know how topical it would become,” she says.

“Unaccompanied minors wasn’t a big question at the time, but the first time I visited Calais I met a 12 year old boy who had travelled on his own and I was so shocked that this was happening in the heart of Europe.

“There were many things I didn’t know could happen in this day and age; people selling organs to pay for passage; incidents of sexual assault; people being sold into the sex or drugs trade.

“Knowing what people have come through it’s terrifying.”

Berry-Hart initially turned her Queen’s Park home over as a collection point but it was soon overflowing with tents, sleeping bags and food so Calais Action commandeered a vast warehouse.

“At first I assumed the people in Calais were off bounds and I didn’t know how to help, but I realised there were British people loading their cars and driving over there.”

Berry-Hart whose previous plays include a verbatim play about gay rights in Russia at the Sochi winter olympics doesn’t believe in being politically neutral as a writer.

“People from major aid charities try to divorce politics from the crisis but politics creates refugees.

“This humanitarian disaster has been made by the politics of the country from where they come and the politics of the country dealing with it.

“You can’t separate politics from refugees.”

She wrote Cargo as a thriller because: “I’m conscious that political subjects can be boring and people switch off.

“People need to be caught up in the story and dramatically it’s quite exciting to explore the power dynamics and shifting allegiances among a close group of people who don’t know each other and don’t know who they can trust.

“Who is going to survive the border crossing and who is going to betray them?”

Ultimately though she hopes to leave audiences with a better understanding of why the refugees make the journey.

“Wherever you sit on the political spectrum I want people to imagine what if this happened to us, what if our country was wracked by civil war?

“Would you pick up your children and run? I would.

“I want to try to get them to empathise with how it would feel to leave your country and travel with strangers and an understanding of why people put themselves through that.”

Also an author, she’s working on a children’s picture book about a child refugee, but feels theatre can be more topical.

“You often write a book but then it doesn’t come out for a while. It’s much easier for theatre to respond quickly to public events.”

Cargo runs at the Arcola, Hackney until August 6 arcolatheatre.com