JEREMY Corbyn is clearly a glass half-full politician; perhaps he has to be.

Expectations were high before Super-Thursday that the real political story of the various elections was - whither the Labour leader? And while some results did not pan out as many had expected, the fortunes of the Islington MP still dominate the fall-out.

While a bad hit in Scotland was always factored in, the scale of it still came as a terrible shock for the party. The Tories, yes, for so long the nasty Tories, actually leapfrogged Scottish Labour under the ebullient leadership of Ruth “champion of the Union” Davidson.

This is a watershed moment for Labour. While Kezia Dugdale has pledged to carry on, the mountain looks to be of Himalayan proportions.

In England, the drubbing that had been expected – analysts had predicted council seat losses for Labour of up to 300 – did not materialise; the scale of losses was much smaller. With a sense of relief, Mr Corbyn declared Labour had “hung on”.

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The wily Labour peer and shadow cabinet member Lord Falconer said it had been a “mixed picture”, suggesting that no one had expected Labour to gain hundreds of seats, particularly in such a volatile period when the public was still making up its mind about the main parties.

Indeed, John McDonnell, the shadow chancellor, had sought to instil in colleagues the line to take when cross-examined by the media; that the comparison to be made was that of the last General Election when Labour trailed the Tories by seven points rather than the comparison with 2012 when, in the same seats, Ed Miliband picked up a healthy gain of 800. And, of course, he went on to lose.

The lowering of expectations was also attempted by Tom Watson, the deputy leader, who suggested people should not take any notice of the numbers as Mr Corbyn had only been at the helm of his party for eight months. The message was clear: calm down and carry on.

One the drubbing south of the border had not materialised, Mr McDonnell went on the offensive and urged the Corbyn critics within Labour’s parliamentary party to “put up or shut up”.

But while politicians always seek to massage the message, particularly at times of elections, the reality is that Labour should be gaining a whole host of seats at this time in the electoral cycle; not least as Tory divisions from the cabinet down play out over Europe. If not now, when, one has to ask of Labour making gains?

The performance in England and the comparatively good one in Wales topped off by the win by Sadiq Khan in the London mayoral election allowed Mr Corbyn to point to the half-full glass.

But some of his closest colleagues have harboured the deepest of reservations about their leader’s ability to do what matters: win the 2020 election.

Indeed, after most of the results came through Ian Murray, Labour’s only Scottish MP and the shadow Scottish secretary, could not hold back and made clear voters did not, at the moment, see Labour under Mr Corbyn as a "credible party of future government". Quite an indictment despite the caveat.

Senior backbencher David Winnick said Mr Corbyn was hindering not helping the party and should consider his position, Neil Coyle the Bermondsey MP warned Labour was "moving away from government" under the veteran left-winger while his colleague Jo Cox said the “clock is ticking” on Mr Corbyn’s leadership.

Then there was the telling coincidence of Andy Burnham, the shadow home secretary, letting it be known as the results began to come through, that he was considering quitting Westminster to run for the mayoralty of Greater Manchester in 2017.

Yet any attempted plot to oust the leader does not appear imminent.

The rebels certainly would not want to do anything ahead of the June 23 EU referendum for fear it might harm the Remain campaign.

The silence this week from senior Labour backbencher Dame Margaret Hodge over claims she was preparing, with the support of colleagues, to launch a stalking horse challenge to Mr Corbyn was deafening.

However, the rebels themselves have problems.

Even if they could mount a challenge, given the leader’s huge 60 per cent mandate, he would likely win any rematch. Then there is the little matter of there being no clear alternative candidate to be leader; Alan Johnson, the former Home Secretary, has insisted many times he is not interested.

So this is the rebels’ dilemma. Convinced Mr Corbyn cannot win the next election, they can either allow him to continue to 2020 and crash and burn even worse than Mr Miliband did in 2015 and begin the long rebuild thereafter or they can try to find a means of ousting him and getting a new leader in by 2018.

Some 21 years ago, the embattled Tory premier Sir John Major urged his detractors to “put up or shut up” as Mr McDonnell has done.

The Conservative leader’s eurosceptic critics eventually slunk back from wielding the knife. But Sir John was fatally wounded by the constant sniping and we all know what happened at the subsequent election in 1997. Perhaps the same fate awaits Mr Corbyn.