Watch: Health campaigner has no IRA baggage as she takes Sinn Fein helm at Stormont

She sought to raise awareness as minister for rural development by funding a suicide prevention officer in her Mid Ulster constituency.

She said: “I have no doubt that Niamh Louise Foundation’s project will mean that for those who may suffer in silence, they will now have the opportunity to break that silence and find the help and support they need.”

Friends argue that her spectacular rise to power aged just 40 has been marked by a passion for helping people.

She faces a daunting challenge to rebuild political relations at Stormont and piece together the shattered powersharing coalition when she could become Deputy First Minister.

In the Assembly she announced - in characteristically quick-fire fashion - that her party would not be re-nominating Martin McGuinness for the position.

“If we are to return to this chamber there must be real, meaningful change. There must be respect and equality for all sections of society.”

The former agriculture minister has been a prominent face articulating the party’s position in recent weeks since Mr McGuinness became ill.

She has been involved in republican politics from her teens, has held various senior positions within Sinn Fein and has a background in social welfare issues.

She is a member of Sinn Fein’s ruling Ard Chomhairle.

Mid Ulster MP and party colleague Francie Molloy watched her progress through local politics and said she had a thoughtful approach to dealing with people.

“She is not one of these people who rushes into commentary on things, she would be a good listener and sit back and observe and take account of things, so she would not be a reactionary sort of person.

“She would certainly be more on the lines of consideration and looking at all the effects of it and looking at the good points of people as well as the issues.”

Mrs O’Neill was elected to the devolved Assembly in 2007 following the restoration of powersharing after years of backroom work for Mr Molloy.

The mother-of-two was the first woman to hold the position of mayor on Dungannon and South Tyrone Borough Council and also one of the youngest.

While agriculture minister she decentralised government services from Belfast and won praise for efforts to boost rural development - although a DUP ministerial colleague won a court challenge against her bid to divert funds towards that area.

She has none of the former IRA baggage carried by some party colleagues.

One of her first actions as health minister was to lift the lifetime ban on gay men donating blood.

She has also supported a cross-border cardiology service credited with saving the lives of 27 patients from Co Donegal in its first nine months.