Labour leader Ed Miliband has said he would have intervened if he had witnessed the throat-clutching assault on Nigella Lawson by her husband Charles Saatchi.
Mr Miliband said he recoiled when he saw images of the attack, telling the Guardian: "I thought they were horrifying pictures."
Both he and Government minister Alistair Burt - who was speaking in a BBC radio interview - said they would have stepped in, after Deputy Prime Minister Nick Clegg had faced criticism for suggesting the incident could have been "just a fleeting thing" during his weekly radio phone-in.
Miliband said: "Honestly, if you are passing by something like that happening - our duty is to intervene. If I had been in that situation, passing by in those circumstances, the right thing to do is to go up to somebody involved in that and say, 'What's going on?'."
While this newspaper abhors violence against women, we do not see condemnation of an assault as a reason to intrude into the complexities of a couple’s marriage.
Some people have called for us to drop Mr Saatchi’s regular column on photography, which appears today in the newspaper.
Our view is that the police decided a caution was a proper response to the offence. It is overstepping our jurisdiction to go further.
Should a person who has accepted a caution be barred from writing about art? Should the Saatchi Gallery be closed? Should he face total ruin?
We decline to go beyond what the law considers appropriate.
We believe that Mr Saatchi’s column is not relevant in its subject matter to recent events — and that it would be irrational and unjust to drop it just because it has been a wretched week for this marriage.
The shadow home secretary said Nick Clegg demonstrated "how little he understands violence against women" after he said Charles Saatchi's assault of wife Nigella Lawson could have been "a fleeting thing."
The Deputy Prime Minister has risked criticism after using the word "fleeting" to describe an incident of alleged domestic violence between Nigella Lawson and her husband Charles Saatchi.
Asked on his LBC radio phone-in what his reaction would have been if he had been present during the alleged altercation, Nick Clegg urged caution because the details of the incident, for which Saatchi accepted a police caution for assault, were not clear.
"When you see a couple having an argument, most people just assume that the couple will resolve it themselves," Mr Clegg said.
"If, of course, something descends into outright violence then that's something different.
"I just don't know - there was this one photograph - whether that was a fleeting thing."
He admitted he had not realised there were more photographs and said that generally his instinct would be to protect the weaker person if physically threatened.
The husband of Nigella Lawson - art collector Charles Saatchi - has spoken about why he took a police caution for assaulting her.
He told the London Evening Standard: "Although Nigella made no complaint I volunteered to go to Charing Cross station and take a police caution after a discussion with my lawyer because I thought it was better than the alternative of this hanging over all of us for months."
Mr Saatchi accepted the caution after photographs emerged appearing to show him grabbing his wife's throat.