Harriet Harman has admitted that she should have stood for the Labour leadership after Gordon Brown resigned in 2010. In an interview on Sunday, Harman compared the current situation within her party to the "painful" experience of Labour in the 1980s.

Appearing on the Sophy Ridge on Sunday show on Sky News, the politician spoke about the current divisions in the party and asked if she regretted not having stood as leader, Harman said: "In a way I do."

Harman became acting leader in the wake of Gordon Brown's resignation following defeat in the 2010 election – the moment at which she says she should have stepped up. However, the longest continuously serving female MP, who has dedicated her career to pushing for women's rights, said it was a "mystery to her" why she didn't.

She said: "I became acting leader and suddenly realised I could do it. At that moment, I should have stepped forward," adding "I think the world is full of men who aren't up to the job pushing forward and loads of women who are up to the job who don't and for that moment I was probably one of them."

Commenting on the state of the Labour Party and assertions in her new book A Woman's Work,published last week, that in the 1980s "infighting turned people off voting for us", Harman admitted the party was experiencing "painful echoes" of that time. She added that the party had to "get its act together."

Adding further pressure to Corbyn's leadership, she said the party was not providing the opposition that was currently needed because it did not have the support of the public.

She said: "I think you can't be an effective opposition if you don't have enough public support because the government doesn't need to worry about you."

Asked about the paradox of the Labour Party – prided as the party for women, she said, and the party with the most female MPs – failing to promote women to top jobs and Corbyn's role in this, Harman defended the party leader and said he was "not the first" leader to preside over inequality within the party.

However, when asked about Corbyn's stance on online abuse endured by Labour's female MPs, at times enacted in his name by supporters, Harman was less forgiving. She said Corbyn needed to do more than just condemn the behaviour of online trolls.

She said: "It's not good enough to say 'it's all awful,' when you're the leader of a party you're in a position to do something about it."

The interview was broadcast on the same day that the Mail on Sunday reported that Harman had given her backing to Keir Starmer as the person to take the party forward. According to the Mail on Sunday, in a leaked tape, Harman said: "It is a miserable time for Labour, but when we hear Keir speak, we feel optimism in difficult times."

Harriet Harman
Harriet Harman is the longest continuously serving female MP.Getty