Benedict Cumberbatch was focused on playing Vote Leave mastermind Dominic Cummings with “sympathy and understanding”, the writer of a new Brexit-based drama has said.

The 42-year-old plays Cummings, a key “behind the scenes” player, in the new show about the successful, data-driven Vote Leave campaign, ‘Brexit: The Uncivil War’.

Hinting at what Cumberbatch’s version of Cummings will be like, writer James Graham has revealed the ‘Sherlock’ star was focused on finding “the humanity” in the role.

“He met Dominic, I think they got on really well,” he said. “Benedict’s absolute obsession all the way through was to make sure that it wasn’t too one-sided.

“That the film wasn’t blaming him.”

The political thriller will air on Channel 4 in January and is set in the run-up to the EU referendum.

It explores the “myriad tactics employed to swing one of the most surprising referendum results in living memory”.

The drama was announced amid controversy over the political impact of data-mining, with investigations examining possible links between Vote Leave’s campaign and data companies.

Before the referendum, Cumberbatch was vocal in his opposition to Brexit.

He was one of almost 300 actors, musicians, writers and artists who signed an open letter urging voters to keep the UK part of the EU.

Explaining why he decided to pen the show, Graham said he had a “responsibility” to write about Cummings.

“A mainstream audience, a popular audience, would not have heard of Dominic Cummings,” he said.

“I wouldn’t have heard of Dominic Cummings throughout the entirety of the campaign and I consider myself reasonably engaged and in-tune.

“I think the responsibility, if you’re going to interrogate what decisions were made and who was responsible for those decisions [is] to put the strategist behind the scenes in the spotlight.”

In July, the Electoral Commission fined Vote Leave £61,000 for breaking campaign spending rules.

The elections watchdog found more than £675,000 spent with data firm Aggregate IQ via another campaign group should have been declared by Vote Leave. It meant Vote Leave exceeded its legal spending limit of £7 million by almost £500,000.