BritBox, the British-centric niche streaming service from BBC and ITV, announced a new partnership with writer-producer Jeff Pope on Saturday to produce two new series starring Stephen Merchant (“The Office”) and Harry Potter series alum Timothy Spall.

Merchant, who directed the upcoming WWE feature “Fighting With My Family,” will star in one series as convicted serial killer Stephen Port, who received a life sentence in 2016 after being found guilty for the rape and murder of multiple men.

The series, written by Neil McKay with the working title “The Barking Murders,” focuses on the families of the victims.

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Pope, an Oscar nominee for co-scripting the 2013 drama “Philomena,” will also co-produce “The Hatton Garden Heist,” which was created and written by Pope and will star Timothy Spall (“Harry Potter”).

“Throughout the past year BritBox has continued to thrive in an increasingly competitive space,” BritBox President Soumya Sriraman said in a statement. “Our service has the right mix of one-of-a-kind originals, unrivaled British talent, and an enviable library of classics that proves even in a field dominated by Goliaths, David still has a shot.”

The partnership comes one month after BritBox announced it now serves over 500,000 paying subscribers.

Known for its library of classic and current British content, the SVOD service features exclusive premieres and current British-native shows with most content becoming available within 24 hours after its U.K. premiere.