Britain's Got Talent was originally planned for 2005-2006 under the title 'Paul O'Grady's Got Talent', with a pilot filmed in September 2005 featuring judges Simon Cowell, Fern Britton, and Piers Morgan.

Paul O'Grady stepped down as host after a row with ITV over renting studios for his teatime show, which had moved to Channel 4; he refused all future work for ITV, forcing the show's delay.

The unaired 2005 pilot episode was not broadcast until it appeared as part of a documentary series called The Talent Show Story in January 2012.

Simon Cowell devised the show's format, drawing inspiration from classic British variety talent shows Opportunity Knocks (1949-1990) and New Faces (1973-1988).

Before the show finally launched, David Hasselhoff and Cheryl Cole were originally planned as judges alongside Cowell, but both resigned before broadcast, leading to Piers Morgan and Amanda Holden joining the panel instead.

In 2009, Kelly Brook was announced as a fourth judge for series 3, but the format change was dropped less than a week after auditions began, and she was credited only as a guest judge.

During series 6 auditions, David Walliams' mother Kathleen, who happened to be in attendance, temporarily filled in for a late Simon Cowell during a series 10 audition.

Live episodes were broadcast from The Fountain Studios in Wembley (also used for The X Factor) until its closure in 2016, after which the show moved to Elstree Studios in 2017 and then to Hammersmith Apollo from 2018.

During series 14 (2020), filming was disrupted by the COVID-19 pandemic, requiring a virtual audience, social distancing, pre-recorded semi-finals, and a changed voting system.

For series 18 (2025), auditions were filmed entirely in Blackpool's Winter Gardens rather than London for the first time in the show's history.

The live final of the third series attracted a record 17.3 million viewers with a 64.6% audience share, making it the highest-watched moment in the show's history.

In 2023, judge Bruno Tonioli broke the rule limiting hosts to one Golden Buzzer press by using it a second time; this was allowed to stand and led to ambiguity over usage limits in later series.