The veteran Labour MP refused four opportunities to voice regret for saying at the height of the republican bombing campaign that "every defeat of the British state is a victory for all of us", saying only that she had "moved on".
She is on course to be Home Secretary if Labour wins the election on June 8 – a job she claimed her three years as a young trainee in the department helped qualify her to do.
She also defended once voting against banning terror groups including Al Qaeda, because some on the list were "dissidents" rather than terrorists.
It was the latest interview given by the Shadow Home Secretary to plunge many Labour election activists into despair.
It was 34 years ago. I had a rather splendid afro at the time
The leadership was urged earlier this month to keep her off the air after a she disastrously muddled a police policy.
Ms Abbott was grilled yesterday by BBC One's Andrew Marr over her beliefs about a range of security issues.
She first tried to dismiss her 1984 comment hailing defeats of "the British state" as coming from a now-defunct newspaper.
Pressed to say if she now regretted her support for the IRA in the 1980s, she said – apparently getting the number of years wrong: "It was 34 years ago. I had a rather splendid afro at the time.
Abbott was grilled by Andrew Marr on her beliefs
"I don't have the same hairstyle and I don't have the same views, and it's 34 years on.
"The hairstyle has gone and some of the views have gone."
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Asked again if she regretted the remark, she repeated :"The hairstyle has gone, the views have gone. We've all moved on in 34 years. Haven't you, Andrew?"
Asked a third time if she felt regret, she demanded to know what specifically she was being asked to take back.
Ms Abbott tried to dismiss her 1984 comment
Told that it was her comments about defeating the state and how IRA violence was caused by the British military presence in Northern Ireland, she repeated that it was "34 years ago, I've moved on."
She said the same when Mr Marr read out the exact quotation.
Later on the same show, Home Secretary Amber Rudd hit back: "What I would say to Diane Abbott is I have changed my hairstyle a few times in 34 years as well, but I have not changed my view about how we keep the British public safe."
When Mr Corbyn – who is under pressure over his own past closeness to Sinn Fein/IRA – was asked about his former girlfriend's comments, he told ITV's Peston on Sunday: "Diane's hairstyle is a matter for Diane."
Ms Abbott said she had a "rather splendid afro at the time"
Pressed further, he said: "We learnt, all of us, a lot from the whole experience of Northern Ireland.
"Remember what it was like… in the late 70s and early 80s, the military presence all over Northern Ireland, the huge divide between communities … the idea that there'd be a military solution when we knew there wouldn't be.”
Earlier, Ms Abbott assured Mr Marr that she no longer backed scrapping MI5, because it had been reformed since 1989 when she signed a parliamentary motion condemning such "conspiratorial" groups.
She also backed the police having a DNA database of criminals. After claims she said in 2010 that even guilty people's DNA should not be stored, she said she did not know where that story came from but had been thinking of a local child having their sample taken who had committed no crime.
Diane Abbott's most controversial quotes Fri, April 7, 2017
Outspoken Shadow Home Secretary, Diane Abbott holds strong opinions which does not always go down well.
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Abortion is an issue of conscience for the Labour party.
She defended voting against a string of anti-terror laws, saying Conservatives including Theresa May and Brexit Secretary David Davis had sometimes joined her and Mr Corbyn in the voting lobbies because they shared concerns.
Asked specifically about voting shortly before the 9/11 attacks on America against banning Al Qaeda and other Islamist militant groups that went on to commit atrocities, she said it was because some on the list were "dissidents in their country of origin", not terrorists.
Asked why she should be trusted to run the Home Office, the 63-year-old said: "I think there's something to be said for a Home Secretary who's actually worked in the Home Office.
"I worked in the Home Office for nearly three years as a graduate trainee and I know how it works from the inside."
Her history of campaigning as a young woman "with diverse communities" and her 30 years' experience as a constituency MP seeing how political decisions "impact on ordinary people" were also good qualifications, she said.