Mark Read (b. 7 November 1978, Kingston Upon Thames, Surrey, England), Ben Adams (b. 22 November 1981, Middlesex, England), Christian Ingebrigtsen (b. 25 January 1977, Oslo, Norway), and Paul Marazzi (b. 24 January 1975, Wanstead, London, England) were formed in 1998 by the management team of Tim Byrne and Vicky Blood. They signed with Columbia Records in February 1999 and released "Be the First to Believe" in Summer 1999. In 2000 they achieved two number ones with a cover of A-Ha's "Take on Me" and it's follow up "Same Old Brand New You".

In 2001 the band toured Asia, where they were well-received. The music video for their single "No More" was filmed in Singapore. During the Indonesian leg of their tour in the Taman Anggrek Mall, four teenage girls were killed in a stampede.

Their third album, Make It Good, featured a sound closer to traditional rock music, but was to be their last studio project. The album's title track narrowly missed the top 10, then on 8 October 2002, Paul Marazzi left the group citing personal reasons, and A1 subsequently decided to split.

They released The Best of a1, a compilation album throughout South East Asia in January 2004, featuring all their singles (excluding "Be the First to Believe"), two previously unreleased concert recordings and three previous B-Sides. Another compilation album was released in February 2009 following Ben Adams appearance on Celebrity Big Brother.

Since their split majority of the groups members went off to pursue solo projects whilst some went onto producing and song writing. Ben Adams stepped out of the A1 bubble when he released his solo single, "Sorry", which reached #18 in the UK in April 2005. Adams was a contestant on Celebrity Big Brother series, He finished 5th in the shows finale .

Since 2003 Christian Ingebrigtsen started his career as a solo artist. His debut was the specially written duet "In Love with an Angel" for the new talent Maria Arredondo and himself. The song became a smash hit, staying 3 months on the top 10 list of VG-Lista Topp 20 (Norway's official single chart). In May of the same year he made his debut as a solo performer with the song "Things Are Gonna Change".

After a1 disbanded in 2002, Mark Read focussed on writing for other artists, signing a publishing deal with Metrophonic. Read has written and collaborated with a number of international artists, such as: Charlotte Church Joe Brown , Sam Brown, Jarvis Cocker, Roger Cook (songwriter) among others. Read launched 'Greatest Lady In My Life', his debut single, at the Tesco Magazine 'Mum Of The Year' Awards on March 1 2009. The single was available for download from retailers such as iTunes and Amazon.com from March 2 2009 along with a 'karaoke' version or backing track of the same song.Mark has also released his first solo album "Peace at Last" in June 2009.

The four band members formed a MySpace group in November 2008 to keep fans updated of their progress .