Question: Do They Know It's Christmas? was the biggest selling single in the UK until the singer who worked with which lyricist took over the title in 1997?

"Do They Know It's Christmas?"  is a song written in 1984 by Bob Geldof and Midge Ure in reaction to television reports of the 1983–85 famine in Ethiopia.  It held this title until 1997 when it was overtaken by Elton John's "Candle in the Wind 1997", released in tribute to Princess Diana following her death.  It was first recorded in a single day on 25 November 1984 by Band Aid, a supergroup put together by Geldof and Ure and consisting mainly of the biggest British and Irish musical acts at the time.  The single was released in the United Kingdom on 3 December 1984 and aided by considerable publicity it entered the UK Singles Chart at number one and stayed there for five weeks, becoming the Christmas number one of 1984.  The record became the fastest selling single in UK chart history, selling a million copies in the first week alone and passing 3 million on the last day of 1984, on the way to becoming the biggest selling single of all time in the UK.  The original version of "Do They Know It's Christmas?"  has sold 3.8 million copies in the UK to date. <SEP> Sir Elton Hercules John, (born Reginald Kenneth Dwight; 25 March 1947), is an English singer, pianist, and composer.  In his five-decade career Elton John has sold more than 300million records, making him one of the best-selling music artists in the world.  He has more than fifty Top 40 hits, including seven consecutive No. 1 US albums, 58 "Billboard" Top 40 singles, 27 Top 10, four No. 2 and nine No. 1.  He has worked with lyricist Bernie Taupin as his songwriting partner since 1967; they have collaborated on more than 30 albums to date.  For 31 consecutive years (1970–2000) he had at least one song in the "Billboard" Hot 100.  His tribute single, re-penned in dedication to the late Princess Diana, "Candle in the Wind 1997" sold over 33million copies worldwide and is the best-selling single in the history of the UK and US singles charts.  He has also composed music, produced records, and has occasionally acted in films.  John owned Watford Football Club from 1976 to 1987, and 1997 to 2002.  He is an honorary Life President of the club, and in 2014 had a stand named after him at the club's home stadium. <SEP> "Whole Again" is the fifth single released from British pop girl group Atomic Kitten's debut album, "Right Now" (2000).  It is the group's biggest selling single to date and was the final single to feature founding member Kerry Katona, who left the group midway through promoting the single.  "Whole Again" was the first single released from the album in Europe, Australia, New Zealand and South Africa.  It was a massive success, reaching number one in several countries, and selling over a million copies in the UK alone. <SEP> Gold: Greatest Hits is the first greatest hits album released by pop group Steps.  It reached #1 in the UK charts.  The lead single from the album was "Chain Reaction" a cover of Diana Ross's 1986 hit, the single reached #2 in the UK charts and was the group's highest selling single since "Say You'll Be Mine/Better The Devil You Know".  The second single from the album, "Words Are Not Enough", a slow ballad was released with a cover of "I Know Him So Well" from Abbamania.  The single was notably Steps' first single to have an accompanying video that was almost fully animated and did not feature a dance routine like their video for "Heartbeat".  The single reached #5 in the UK charts and was their lowest selling single to date.  A release for "Baby Don't Dance" was planned for 2002 but was scrapped due to the group's split although promotional copies surfaced before the release of The Last Dance.