𝗗𝗨𝗙𝗙𝗬 - 𝙈𝙚𝙧𝙘𝙮 2008

"Mercy" is a song performed by Welsh singer Duffy, released as the second single from her debut studio album, Rockferry (2008). Co-written by Duffy and Steve Booker and produced by Booker, it was released worldwide in 2008 to critical acclaim and unprecedented chart success. As Duffy's first international release, the song is credited with firmly establishing her career and is now considered her signature song. "Mercy" received comparisons to Duffy's previous single, "Rockferry". Critical reviewers of "Mercy" noted similarities between the song to releases by Aretha Franklin, Dusty Springfield and the Supremes, as well as contemporaries such as singer Amy Winehouse.

"Mercy" was nominated for several awards in 2008, including the Grammy Award for Best Female Pop Vocal Performance at the 51st Grammy Awards. Well received by the public, "Mercy" peaked at number one on the UK Singles Chart in February 2008, remaining atop the chart for five weeks, and went on to become the third-best-selling single of 2008 in the United Kingdom, with sales of over 500,000 copies in the UK that year. It achieved worldwide chart success, topping the charts in Austria, Germany, Greece, the Netherlands, Norway, Republic of Ireland, Switzerland and Turkey, and peaked within the top five of the charts in Belgium, Denmark, France, Italy, Japan, New Zealand, Romania, Spain and Sweden. Duffy attributed the chart success to the fact that "everyone is searching for liberty ... from themselves or from the world they’ve created around them" and "everyone would like to be set free". It is Duffy's best-selling single to date.

The song has been covered several times since its original release, most notably by the cast of American musical television series Glee as well as by both The Fratellis and OneRepublic on BBC Radio 1's Live Lounge. The Glee version charted on the UK Singles Chart and in Ireland, and Duffy herself performed the song for the Live Lounge. The song was performed live at various music festivals as well as on Duffy's 2008–09 tour. The main-release music video, directed by Daniel Wolfe, has been viewed on video sharing website YouTube over 80 million times. Lynda Carter released her version of the song on her 2018 album "Red Rock & Blues."

"Mercy" was written by Duffy and Steve Booker during the final stages of completion for Rockferry. In an interview with Mojo, Duffy noted that she "felt something was missing and 'Mercy' was that missing thing", saying that herself and Booker were "writing it literally at the end, when the strings were being put on 'Rockferry' and 'Warwick Avenue". Duffy first met Booker by chance because she bought the flat in Ladbroke Grove that Booker had been renting. Booker's girlfriend met Duffy and then introduced the pair. Duffy has later noted of the experience:

"We went for coffee and I had this gut feeling that we should write together. I asked Jeanette [Lee] what she thought and she just said, we’ve made this record so go and have fun, be creative. By the end of hanging out in the studio for two weeks we had 'Mercy' and 'Stepping Stone'."

The main-release music video for "Mercy", directed by Daniel Wolfe, features Duffy standing on top of a platform performing the song. Featured in the video are Northern soul dancers who dance to "Mercy". Choreographed by Natricia Bernard, the dancing involves elaborate moves, including the use of fire. "Mercy" was nominated for two awards at the UK Music Video Awards, for "People’s Choice Award" and "Best Pop Video". The music video was released to the UK iTunes Store on 26 January 2008, being the first release of "Mercy". In reaction to the video, RealMusic noted that Duffy "does manage to stand atop those platforms very well and sing without falling off in [the] video, so top marks for that".

A second music video release was made for the United States market, directed by Adria Petty.[66][67] It shows Duffy performing live on stage whilst people dance to the song. The US version was given a positive review by Nick Levine of Digital Spy, who wrote that "It's glossy, full of young, good-looking types and proudly features a drum with Duffy's name printed on its skin – hey, that's success for you."