SOME credit is due to Chris Leslie for at least attempting to challenge Jeremy Corbyn over economic policy, even if he parades his own ignorance in doing so.

Leslie told the Independent that a Corbyn government couldn’t target the £120 billion of tax revenues lost annually through avoidance, evasion and system failure or some of the £93bn handed to the corporate sector every year in tax reliefs and subsidies because “it wouldn’t materialise.”

Note the closely reasoned argument. You can’t try it because it won’t work.

Yet Leslie was part of the Labour leadership that criticised corporate non-payment of legitimate taxation in the general election campaign and proposed a measure of tightening up.

Much of the research behind Labour’s position was carried out by Richard Murphy who has assisted Corbyn in elaborating his economic policy.

This would involve increasing staff at HMRC and Companies House to enhance tax collection, introduction of effective anti-tax-avoidance legislation and the aim of country-by-country reporting for transnational corporations.

By quoting the headline figures of £120bn and £93bn, neither Murphy nor Corbyn implies that these huge sums will immediately find their way into the Exchequer.

But a government serious about curbing excesses and giving institutions sufficient resources to tackle them could make tangible inroads.

Such an approach ought to commend itself to all shades of opinion within Labour, but not apparently to the shadow chancellor.

While Corbyn is speaking all over Britain attracting audiences several hundreds strong — and even over 1,000 — telling them that there is more to politics than austerity and austerity-lite, Leslie is holding meetings with the corporate sector.

He wants to win back lost ground with the “business community” — territory forfeited through Labour’s “attitude to business and markets.”

Leslie, who is backing Yvette Cooper for leader, believes that Labour should have spelled out some large-scale spending cuts before the election to show its commitment to clearing the deficit.

That would certainly have rallied Labour troops canvassing on the doorsteps.

He has already single-handedly ditched Labour’s commitment to raising the top rate of income tax from 45p in the pound to 50p and the proposed mansion tax on properties worth over £2 million on the grounds that there were “some anxieties” that it might be extended to a lower level.

The shadow chancellor counterposes his approach, which includes backing “sensible savings” advanced by George Osborne, against Corbyn’s “starry-eyed, hard left” economic strategy and believes “common sense will prevail.”

He has told the Murdoch media, in common with leadership hopefuls Cooper and Liz Kendall, that he would refuse to serve in a shadow cabinet led by Corbyn.

The left-wing front-runner is committed, if elected, to build a shadow cabinet drawn from all wings of the party, but few supporters would shed tears over the absence of pro-business prima donnas.

They rattle on about leaders and potential prime ministers being “credible,” but they don’t come clean on how candidates’ credibility is to be assessed or by whom.

Neither Corbyn nor any candidate who prioritises investment for jobs, living standards, health, education and social solidarity will ever be deemed credible by the mass media, the City or the parliamentary elite.

But the tens of thousands of mainly young people who have engaged with the Corbyn campaign in recent weeks and want a different kind of politics have other ideas about credibility.

If the dead hand of New Labourism reasserts itself at the Labour Party tiller, it will alienate them and steer Labour towards political irrelevance.