The Ulster Unionist Party's only MP has resigned from the party and announced her intention to stand in the British general election as an independent.
North Down representative Sylvia Hermon's widely anticipated departure from the UUP comes after she voiced opposition to the party's electoral alliance with the Conservative Party.
'It is now my intention to stand my ground, fighting the forthcoming general election as an independent and fighting to win,' she said.
Mrs Hermon had already indicated that she would not stand in North Down under the joint UUP/Tory banner and had been taking a period of time to decide whether to go it alone.
As well as criticising the link-up with the Conservatives, the ex-lawyer has also hit out at the UUP's decision to vote against the devolution of policing powers to Stormont.
Immensely popular in the strong unionist constituency, the widow of former Royal Ulster Constabulary Chief Constable Jack Hermon will have high hopes of retaining her seat.
She said: 'As we approach the end of this parliament, with the Easter recess beginning next Tuesday and dissolution expected shortly thereafter, the mandate given to me at the last general election to serve the people of North Down as an Ulster Unionist is virtually at an end.
'The distance, however, between me and my party has become so great over recent months that I have decided to resign from the Ulster Unionist Party with effect from midnight last night.
'I have taken a considerable amount of time to think and to reflect before coming to this decision, but I believe it to be the right one for the party and for me.
'That said, leaving the Ulster Unionist Party causes me profound sadness, as I have been proud to serve it at Westminster since first becoming its MP for North Down in 2001.'
UUP leader Reg Empey expressed his 'deep regret' at the decision.
'I wish to thank her for her contribution to Ulster Unionism since her election in 2001,' he said.
'I believe that the values we share far outweigh the differences in approach to some issues.
'The party's major policy decisions have been reached after widespread consultation and have been unanimous.
'I wish Lady Sylvia and her family well in the future.'