Doug Beattie resigned from the Ulster Unionist Party on Sunday.

In a letter to party leader Jon Burrows, Beattie stated his membership was no longer tenable and cited concerns over relations within the party.

Beattie said he had persuaded Burrows to join the UUP and later regretted the decision.

He claimed an insidious element within the party had been briefing against him on selections and other issues.

Beattie said the final matter involved the party reopening a disciplinary case over tweets from four years ago.

A UUP spokesperson said the party management board had met on Thursday and agreed a course of action regarding concerns about Beattie's conduct and judgement.

The spokesperson said the party did not accept Beattie's characterisation of recent events and thanked him for his years of service.

Beattie was first elected to the Northern Ireland Assembly in 2016 for Upper Bann and had previously served as party leader from 2021 to 2024.

He had been facing deselection by his constituency association ahead of the next assembly election.