YVETTE Cooper delivered the strongest attack yet on so-called Corbynomics, saying her fellow leadership candidate's policies were “not radical and not credible”.

In her most hard-hitting speech of the campaign, the Shadow Home Secretary insisted she had to speak out against Jeremy Corbyn’s policies even if it lost her votes.

Declaring bluntly that she was offering a “much more feminist approach to our economy” by putting the family at the centre of it, Mr Cooper told an audience in Manchester: “Universal free childcare should be as much the infrastructure of the modern economy as trains, planes and boys toys.”

In a full-on attack against Mr Corbyn’s policies, she asked: “Tell me what you think is more radical. Bringing back Clause IV; spending billions of pounds we haven’t got switching control of some power stations from a group of white middle aged men in an energy company to a group of white middle aged men in Whitehall.

“Or extending Sure Start; giving mothers the power and confidence to transform their own lives and transform their children’s lives for years to come.”

She also accused the left-winger of trying to “trash” Labour’s reputation as an internationalist party.

“We should stay in the EU, stay in the European Court of Human Rights, stay in Nato; sorry, Jeremy, internationalism is a core Labour principle and I will always fight for it,” declared Ms Cooper.

The Yorkshire MP dismissed as “bad economics” Mr Corbyn’s plan to print money – used previously to shore up the banks - to support infrastructure spending.

“Quantitative easing was a special measure when the economy collapsed, liquidity dried up, interest rates fell as low as they could go. But printing money year after year to pay for things you can’t afford doesn’t work.”

Suggesting Mr Corbyn would split the party, she robustly denounced the idea that power did not matter as long as Labour principles remained intact.

“Tell that to all those people who are being hit by Tory Government...with no one else to stand up for them than the Labour Party, than us. That’s our job. We can’t walk away.”