A Sinn Fein MP who caused controversy after posing with a Kingsmill branded loaf on his head on the anniversary of the Kingsmill massacre has resigned.
Barry McElduff, who was last week suspended by his party for three months, said he had now decided to quit as an abstentionist member of parliament for West Tyrone.
"It is with great sadness that, after more than 30 years as an active Sinn Fein member and public representative I am tendering my resignation as MP for West Tyrone," he said.
"The reason I am doing so is because of the consequences of the Twitter video which has caused such controversy over the last week."
Mr McElduff reiterated his insistence that he had not meant the video as a reference to the sectarian murders of 10 protestant workmen by republican paramilitaries near the south Armagh village of Kingsmill in 1976.
He said his greatest regret was the "deep and unnecessary hurt" his video had caused the Kingsmill families.
"I again offer my profound apology to those families and to the wider victims community," he added.
"Had I been conscious of the connection to the terrible atrocity at Kingsmill I would certainly not have posted that tweet. I genuinely did not make that connection, not for a second did I make that connection in my mind.
"Kingsmill was wrong, unjustifiable and sectarian. It should never have happened.
The extent of Mr McElduff's original punishment by Sinn Fein - a three-month suspension while still being paid - was widely criticised by unionists.
The sole survivor of the attack, Alan Black, welcomed the resignation.
He told the Press Association: "This past week has been truly awful for me. I am just hanging by a thread.
"But I am glad he has done the right thing."
Mr Black said the fall-out from the Twitter video forced him to re-live the trauma of the attack in which he was shot 18 times.
"I am going to have to take time now to heal," he said.
"I only got involved because of the hurt and disrespect shown to my friends who died at Kingsmill but this whole thing has taken a heavy toll."