Creator Chris Chibnall conceived Broadchurch around 2003 while working on his first series, Born and Bred, and envisioned it as a trilogy from the start.

The show's setting on the Jurassic Coast in Dorset was partly chosen because Chibnall lived there and wanted to improve his work-life balance after years of traveling for shows like Torchwood, Law & Order: UK and Camelot.

The character name DI Alec Hardy and the fictional Wessex Police are references to Dorset-born author Thomas Hardy, whose novels also inspired the name Tess Henchard and a character reading Jude the Obscure.

The town name 'Broadchurch' was invented by Chibnall by combining two real Dorset hamlets, Broadoak and Whitchurch, in homage to Thomas Hardy's style of compound place names.

Chibnall wrote the first series' script on spec after finishing work on Camelot, using whiteboards from May 2011 to map out characters and plot before it was picked up by ITV.

Chibnall only decided that Joe Miller, DS Ellie Miller's husband, would be the killer several weeks into writing, which reshaped the series to focus on two families instead of one.

The roles of Reverend Paul Coates, DS Ellie Miller and DI Alec Hardy were all offered directly to Arthur Darvill, Olivia Colman and David Tennant respectively without auditions, as they were Chibnall's first choices.

Unlike most British TV dramas, which are shot out of sequence, Broadchurch series one was filmed in script order specifically to help keep the killer's identity secret during production.

To maintain suspense and a raw performance style, actors received minimal rehearsal and were often prevented from seeing filming locations until shooting began, with directors relying heavily on first takes rather than multiple retakes.

During filming of series one, all cast and crew signed confidentiality agreements about the killer's identity, and by the time the final three episodes were shot only 29 people knew who the killer was.

Composer Ólafur Arnalds, a longtime favorite artist of Chibnall's, wrote the series one score for string quartet, piano and electronics in just four months, recording it in only five days inside an empty church in Reykjavík.

Some of Ólafur Arnalds' Broadchurch score was later reused in the trailer for the Fantastic Four movie reboot.

In June 2014, the series two production team was criticized by West Bay coastguards for filming too close to the unstable edge of East Cliff without full safety equipment like stakes, harnesses and helmets.

Author Erin Kelly, who wrote a novel adaptation of Broadchurch, said Chibnall inserted a one-line clue about series two's plot into her book just three days before it went to print.

Broadchurch was adapted into an American version called Gracepoint (2014), also starring David Tennant and written by Chibnall, which had a different ending but was cancelled after low ratings following its single season.