We'll be wading through the wreckage of Labour's profound defeat in Scotland for weeks and months to come, but I'm immediately struck on my return to London that there is nothing uniquely Caledonian about the problem the party faces.
In the afermath of the SNP victory I spoke to a recent English arrival in Scotland who professed that he had little knowledge of the Scottish political system, and was hardly interested in politics at all.
"But, how could anyone vote for Labour with that leader?" he asked rhetorically. I let the pause grow longer, expecting another voter to run down Iain Gray's poor, bruised personality. The new arrival contined: "I mean Ed Miliband, who would vote for him?"
Then, I understood, that it's infectious - the UK Labour party has an "Ed Gray" problem.
Left of centre parties across Europe face a question of what they stand for, and how they deliver the message of their core values in this age of austerity.
There will be lots of lessons for Scottish Labour from the election, but these same hard questions have to be faced by the party at a UK level too, if my reading of the English local election results is right.
If parties don't make a clear offer to voters, and if their leaders don't match expectations of the electorate, traditional supporters cast around for what else is on offer.
I repeat,there is no evidence to suggest that what happened to the Labour party in Scotland is a one off. It could be the beginning of a pattern, and that might be one of the most profound lessons of Thursday night.
The Parliamentary Labour party meets this evening to pick over the election results. The MPs will be addressed by Ed Miliband, we'll be outside listening for the sound of desks being banged in support of the leader.