Pauline Armitage: A UUP member since 1969
The East Londonderry assembly member is a former soldier in the Ulster Defence Regiment and comes from Coleraine.
She used to run an infants nursery store but is no stranger to the harsh realities of Northern Ireland politics, having been a UUP member since 1969.
Mrs Armitage's decision not to back Mr Trimble reflects her doubts over the IRA's latest move to put its weapons beyond use, despite a meeting earlier this week with General John de Chastelain, head of the Independent International Commission on Decommissioning (IICD).
DUP motion backed
At the time she described the discussions as "useful", and said progress had "possibly" been made.
But her subsequent refusal to toe the party line will come as no surprise to observers.
Last June Mrs Armitage denied she was weakening her leader as she backed a Democratic Unionist Party motion calling for the exclusion of Sinn Fein ministers from the executive.
The decision was made on her own without pressure from others, she said, and came after weeks of wrestling with her conscience.
A month earlier she had publicly criticised her party in the assembly for going back into an executive with Sinn Fein before moves by the IRA to put its weapons beyond use.
Assembly 'farce'
Mrs Armitage has also described the assembly as "slightly a farce" because of the issues it debated, such as the prospect of rural post office closures.
Personal electoral defeat is unknown, she claims, although her seat on Coleraine Borough Council - she has been a member since 1985 - was in jeopardy in elections last June.
Mrs Armitage served as mayor for two years from 1995 and specialises in housing and health.
Security concerns are another area of interest following service as a UDR 'Greenfinch'.
She is married and lives on the coast at Portstewart, not far from Coleraine.