[5][6] Prior to her career in politics, Essex worked as a technical secretary at the South Wales Standing Conference from 1971 to 1973.

[4][11] Outside of her career in planning and local government, Essex also worked as a researcher for the Equal Opportunity Commission from 1985 to 1987.

[12] As a councillor, Essex was part of a local group of allied soft left Labour politicians known as the "Riverside Mafia", which also included Davidson, South Glamorgan County Council members Mark Drakeford, Jane Hutt and Julie Morgan, and Cardiff West MP Rhodri Morgan.

[13] It was known for opposing the policies of Jack Brooks and Russell Goodway, the Labour leaders of South Glamorgan in the 1980s and 1990s, and the Cardiff Bay Barrage project which they supported.

Most members of this group, including Essex, later served in Morgan's cabinet during his tenure as First Minister of Wales in the 2000s.

In the same session as the leadership vote, Essex was re-elected as deputy leader and chair of the planning committee.

A left-wing deputy mayor, Paul Morris, was elected by the Labour group to serve under Essex.

To this end, she set up the City Centre Partnership Forum (CCPF) which was made up of stakeholders from the private and public sectors.

Both Essex and South Glamorgan's Labour leader Russell Goodway stated their intention to lead the new council.

Essex's more politically progressive base fell out of favour in the local Labour group, with her supporters being treated as internal opponents of the party.

Essex also stood for the deputy leadership and the chairmanship of the council's planning committee, losing to Houlston and Neil Salmon respectively.

[40] At the assembly election in May 1999, Essex won Cardiff North for the Labour Party with 12,198 votes, a majority of 2,304 over the Conservative candidate Jonathan Morgan.

She was described by BBC News shortly after her election in 1999 as one of the "most experienced" backbenchers in the Labour group led by Alun Michael, the first secretary of Wales.

The committee first met in June 1999 before being dissolved in March 2000 as it no longer matched the responsibilities of any members of the Welsh cabinet, which had been reshuffled earlier that year.

[47][48] A close ally of Morgan's, Essex had publicly supported him in both of his bids for the Welsh Labour leadership in 1998 and 1999.

[50] After the formation of Morgan's coalition government with the Liberal Democrats in October 2000, Essex's ministerial role was renamed Minister for the Environment,[l] with her portfolio now also including sustainable development.

[52][53] In April 2000, Essex pledged to introduce free bus passes for pensioners and people with disabilities in Wales.

Following a public consultation, Essex went ahead with the plan and announced in September that the changes would come into force from April 2001 through provisions made in the UK Parliament's Transport Act, which was passed later the same year.

[56][55] Essex also made a further commitment to scrap local bus fare charges in their entirety for pensioners and disabled people living in Wales from April 2002, including women aged 60 or over and men aged 65 or over, making local bus travel free for these demographics.