Tony Blair admitted he has been left bemused by rise of non-centrists politicians such as presumed Republican presidential nominee Donald Trump and Labour leader Jeremy Corbyn.

"I thought I was pretty good at politics. But I look at politics today and I'm not sure I understand it," the former British prime minister reportedly told a London audience on 24 May.

Blair, who took Labour into the centre ground and spent 10 years in Number 10, also questioned whether Corbyn could take his party to power at the 2020 general election. "[It is not yet a proven concept that Corbynism can win an election," he warned.

The pro-EU campaigner also made an intervention in the Brexit debate, arguing that the UK must take a leading role in Brussels. "Britain, when it seeks to lead in Europe and when it builds the right partnerships and alliances, usually gets its own way," Newsweek reported Blair saying.

The comments came after former interim Labour leader Harriet Harman warned women were being "excluded" from the EU referendum debate. "Half the population of this country are women and our membership of the EU is important to women's lives. Yet men are – as usual – pushing women out," she said. "Women are being excluded and the debate narrowed."

Harman has complained to media watchdog Ofcom in a bid to make sure women are represented better on broadcast outlets in the run-up to the 23 June vote. Corbyn is also expected to raise the issue when he speaks at a Labour rally in Hastings on Tuesday night.

"So far, the referendum debate taking place across the country, has been dominated by men, and mostly Tory men. This needs to change, we need to hear more diverse voices in this important debate, we need to hear more strong women's voices," the left-wing leader will say.

"Women across the country are being let down by a Conservative government that is failing on housing, failing our NHS, failing to create good quality jobs and failing even against its own economic targets.

"We also know that women continue to suffer the impact and burden of callous Tory cuts, much more than men. This government is making the wrong choices, they have the wrong priorities and they are letting women down," Corbyn said.