THIS is a huge moment for Labour; not just north of the Border but south too.

The way Johann Lamont left the stage, in a dramatic fit of pique, has not endeared her to some of her, once close, colleagues.

The problem, party sources argued, was not London dominance or the party structure as Ms Lamont contended but, rather, her lack of leadership.

So who will now become Labour's new champion in Scotland?

Jim Murphy is uncharacteristically quiet. His website has been taken down; which might indicate preparations are being made. But the Shadow International Development Secretary and any other potential candidates are probably looking to see what the Clunking Fist will do.

True to character, Gordon Brown is playing a canny, silent game. Some sources close to the Kirkcaldy MP are adamant he will not stand. But, as in everything, people can be persuaded if the cause is big enough.

Some might argue the Scottish leader cannot be an MP but has to be an MSP. Yet Alex Salmond led his party from the Commons for a number of years.

The question Scottish Labour have to ask themselves is - who do the SNP not want to see opposing us? The clear answer is Mr Brown and Mr Murphy. So, logic would suggest, Labour should choose one of these heavyweights.

The referendum showed that what is required to take on a resurgent Nationalist party with a membership now tripled in size at 80,000 is a big beast; a person who can make the political weather and haul back the momentum in Labour's favour. There is much at stake here. Jonathan Powell, Tony Blair's chief of staff, warned yesterday that the SNP looked as if they could be in power at Holyrood for a generation.

But first things first. The general election is just seven months away. Labour need a politician of stature who can galvanise their party, excite the electorate, scare the SNP and start winning the arguments.

It may well be that Labour's men in grey kilts, headed by Ed Miliband - who just happens to be in Scotland this week - turn up at North Queensferry this week to knock on Mr Brown's door and plead with him to save the party in Scotland and in doing so save the Labour leader's chance of getting into No 10.

Margins might be tight in May and ensuring there is a sizeable Scottish Labour contingent could be the difference between Mr Miliband becoming Prime Minister and seeing David Cameron back in charge.

A loss in May will not only herald five more years of Tory rule but would plunge Labour back into the political abyss of another leadership contest and months of directionless navel-gazing.

And the SNP, meantime, could continue to build momentum - on the back, perhaps, of a doubling or trebling of MPs under the leadership of Alex Salmond - towards the new target of the 2016 Holyrood elections.

So, as leadership contests go, the stakes could not be higher.