Well received by the public, ‘Mercy' peaked at number one on the ’UK Singles Chart’ in February 2008, remaining at the top of the chart for five weeks. It 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 said that "everyone would like to be set free". It is Duffy's best-selling single to date. According to Duffy, "'Mercy' is autobiographical and is about 'sexual liberty' and not doing something somebody else wants you to do". Duffy has also said in an interview with ‘Observer Music Monthly’ that “I sing 'Mercy’ several times a day and it's just like having sex every time".
In a later interview, Duffy said, "The lyrical interpretation is about my own ‘issues and baggage’ and when someone else listens to the song it isn’t about my baggage anymore, it’s about their baggage".
I interpret the song as essentially being no less than a mantra of lust that has been let off the leash for five minutes, and once one starts singing the song, being carried away comes naturally. Despite having never sung the song before today, and only having heard it three or four times, the musical mantra of ‘Mercy’ is simply too tempting to ignore.
Love and peace. Bill xxx