The BBC1 adaptation of JK Rowling's novel The Casual Vacancy has triumphed in the head-to-head battle of Sunday night dramas.

The Casual Vacancy, starring Michael Gambon, Rory Kinnear and Keeley Hawes, and Channel 4's "epic" period drama Indian Summers, featuring Julie Walters in the lead, were pitted against each other at 9pm.

The small-screen version of Rowling's first novel for adults won the most viewers, peaking with 7.3 million.

The drama, set in the seemingly idyllic, fictional English village of Pagford, where residents are at war with each other, enjoyed an average of 6.6 million viewers and a 27.5% share of the audience.

Indian Summers, set in the foothills of the Himalayas during the decline of the British Raj and the birth of modern India, attracted a peak of 3.4 million and an average of 2.9 million (13.4%) including viewers catching up on the plus one channel.

The latest instalment in ITV series Mr Selfridge took 3.5 million (14.5%) with plus one.

Channel 4 said that they were delighted with the launch of their 10-part series, which more than doubled its slot average and was the "highest drama launch since Elizabeth I" in 2005.

The broadcaster's chief creative officer Jay Hunt said: "I'm thrilled that three million people were hooked by Indian Summer's unique mix of political intrigue and raw passion. It's an epic drama, uniquely Channel 4 in tone."

It was revealed last week that The Casual Vacancy's ending has been changed for the small-screen to feature a "redemptive moment", after its scriptwriter decided the novel's conclusion was a little too "grim".

Despite the tweaks, Harry Potter author Rowling has said that she is "thrilled" with the TV adaptation.