In 1999 Gregory was selected as Labour candidate for the
Ogmore constituency, the same constituency as her father, for the
1999 Welsh assembly election. She easily picked up the seat and was appointed as a Labour group
whip in the Assembly. Together with three other whips, Gregory resigned this position in February 2000 after
Alun Michael resigned as First Minister. It was speculated that the three, being loyal to Michael, believed there was a plot against him, and were unwilling to work for Chief Whip
Andrew Davies, who they felt was behind this plot. Shortly after she announced her support for
Rhodri Morgan to replace Alun Michael. Gregory rebelled against the Labour administration in June 2000 when she voted in favour of a building a landmark headquarters building for the Assembly. She called on former cabinet minister
Ron Davies to resign when it was revealed he had applied for jobs outside politics without informing the Labour leadership. When her father suddenly died in December 2001, Gregory immediately declined to seek selection to follow him. It was uncertain whether Gregory would be reselected herself, but she managed to survive and was re-elected in the
2003 election with a 6,504 majority. In December 2005, she was cleared of breaches of the Assembly Code of Conduct, after alleging that a GP in her constituency using an
0870 national rate number was doing so to make "a fast buck". However, she was deemed to have failed to conduct herself in a proper manner. After her re-election she was made Chair of the Social Justice and Regeneration Committee. She was described by the
Western Mail as a "well below par performer by our reckoning" and given a rating of 4 marks out of ten in its assessment of the Assembly Members at the end of the 2003–07 term. However, she increased her majority in the
2007 election. In December 2009, she was appointed to the role of Chief Whip by
Carwyn Jones. She was re-elected at the
2011 Welsh Assembly election with a further increased majority. She announced her intent to stand down at the
2016 Welsh Assembly election in 2015.
Huw Irranca-Davies was selected to replace her as the Labour candidate for Ogmore. She in turn took his previous role as Labour's campaign co-ordinator for the 2016 Assembly election. ==References==