Deacon decides to quit Holyrood in blow for Labour

The Labour MSP, who was part of Donald Dewar's cabinet aged just 35, had once been tipped as a potential leadership contender. But she has not returned to the front benches since rejecting an offer to become social justice minister under Jack McConnell.

Ms Deacon, the mother of two young children, said her decision came after "a great deal of reflection". She said: "I now feel it is time for me to move on, to seek new challenges and to channel my energies in other ways.

"I am standing down at this point, some nine months out from the election, to enable the local party to select a new candidate and to put in place Labour's team for the Scottish parliament and council elections."

Ms Deacon was appointed Scotland's first post-devolution health minister and was widely considered one of Labour's most promising politicians north of the Border.

The Edinburgh East and Musselburgh MSP has been an active back-bencher, speaking out on sexual health and criticising the Executive's relocation policy.

Ms Deacon graduated from Edinburgh University with a degree in social policy and politics, and also earned an MBA.

Prior to being elected to Holyrood, she worked at a senior level in local government, management consultancy and in higher education. The fact she is bowing out will be seen as a loss to Labour.

Ms Deacon, 42, lives with John Boothman, a BBC producer, and their two young children in Musselburgh.

Ms Deacon has also been central to a number of controversies. The late Donald Dewar's chief of staff, John Rafferty, was sacked after he made an unsubstantiated claim that Ms Deacon had received death threats from militant anti-abortion campaigners whom she told to "back off" from protesting outside family planning clinics.

Behind the scenes, she also clashed with Mr McConnell, then finance minister, about how millions of pounds earmarked for health should be used.

When Mr McConnell took over after Henry McLeish's resignation, she refused to accept the social justice brief she was offered. She said she stood down as she did not want to take on the new role while she was pregnant - and not because she thought it was a demotion.

Kenny MacAskill, the SNP MSP who stood against Ms Deacon, said: "I think Susan Deacon will be a sad loss."