A prominent charity has suffered “huge reputational damage” in the fall-out over its employment of a former Sinn Fein employee who later admitted a series of child sex offences.

Sinn Fein is facing questions after it emerged that two former party press officers provided references for Michael McMonagle in 2022, for a job with the British Heart Foundation (BHF), after he was suspended from the party following his arrest in 2021.

Sinn Fein vice-president Michelle O’Neill said both the press officers lost their jobs and are no longer members of the party, adding that she apologised for the hurt and distress caused by their actions.

There have been some apparent irregularities in accounts given about who in the party knew about the references provided and when, and why they did not inform BHF that McMonagle had been under police investigation.

Ms O’Neill is expected to be questioned on the matter at the Stormont Assembly on Monday.

Last month, McMonagle, 42, from Limewood Street, Londonderry, admitted a series of offences, including attempting to incite a child to engage in sexual activity.

Fearghal McKinney, head of the BHF in Northern Ireland, said the charity was dismayed when their due diligence appeared to have been questioned.

He spoke to Ms O’Neill on Saturday, and said she expressed regret over comments she made last week that there were lessons for a lot of people in terms of “due diligence for an employer when they take on an employee”.

“This caused enormous distress and anxiety among our staff and unwavering supporters,” he told the BBC.

“It was quite clear that whenever comments were made about due diligence that there was only one other organisation that employed him since he was employed by Sinn Fein, so clearly there was a reflection on us.”

He said any damage to the charity can undermine their good work.

“When this happened and there was damage caused, as we saw it, to our reputation, added damage we thought around the public comments that were made, we had to do something to make sure that the record was put straight,” he said.

“We’re content that we have done everything in our power in order of keeping all our supporters, all our staff and the wider public that’s connected with us safe, and they know that that’s the standard that the British Heart Foundation applies.”