Not Boris Johnson.  The Prime Minister came on last, a full one-and-a-half hours into the interrogation, by which stage less committed viewers may have tuned out, literally or metaphorically. 

Offering his distinctive amiable, rambling style, Johnson’s performance lacked urgency in getting to the point of the questions being asked. Evading pointed interrogations that, once again, focused on trust, and trying (without much success) to divert discussions about austerity, the health service and his use of language that some found offensive back on to his Brexit deal, he managed to say nothing that was memorable. 

For those who see these debates as offering nothing but risk for the front-runner, the conclusion that “the damage was limited” may count as an acceptable result. 

The standout loser was Jo Swinson. Opinion in the Spin Room behind the studio where journalists and party spokespeople co-habit, divided only between those who felt that she had been “slaughtered” and kinder souls who settled for her having been merely “monstered.”

Seasoned commentators watched open-mouthed at the extent of the studio audience’s cold hostility. Heard in dismissive silence, the Liberal Democrats’ leader had to endure even the audience’s avowed Remainers expressing horror at her role as the country’s leading Brexit reality denier. One doughty Leaver shouted at her “you lost.” It was a verdict that summarised not only the Remain cause in 2016, but her performance in Sheffield. 

Especially telling was the audience’s long memories and unwillingness to forgive and forget the Lib Dems’ support for the austerity measures and broken promises of the Clegg-Cameron years. Try as she did, there was only so far Jo Swinson could backtrack from that record without feigning amnesia or a split personality. 

Few in the Sheffield audience knew or cared enough about the SNP’s patchy record

For a leader who had forlornly gone to court to argue for the right to appear in the first leaders’ debate, Jo Swinson could have been forgiven for wishing she had been excluded from this one as well. It is unclear where or how the Liberal Democrats’ campaign bounces back from here.

The evening’s most adept performer was Nicola Sturgeon. The primarily English audience accorded her the respect that polite, well-brought up folk show to visiting dignitaries from foreign countries. 

This courtesy speaks volumes.  For one of Scottish devolution’s effects has been to remove what happens in Scotland from the sight of the rest of the country. Few in the Sheffield audience seemingly knew or cared enough about the Scottish Nationalists’ patchy record in Holyrood to put her on the ropes about it. 

Instead she was allowed to enthuse about her favourite subject – the right of Scottish people to determine their future. Those carefully selected Scots in the audience who did ask her questions were clearly already in her fan club. Hers was a strong performance, aided by a fair wind.

Whatever the ups and downs of Nicola and Jo, these televised debates are ultimately all about Jeremy Corbyn. 

For unless he can change perceptions about himself and his party (although principally about himself) Labour is not on a trajectory to win this general election. Again, he did not do quite enough to dispel the doubts.

But he did produce the one moment of clarity that these debates should, but rarely do, produce. He dropped his previous refusal to reveal which side he would back if, as Prime Minister, he gets the opportunity to put his revised deal with the EU to a referendum. At last we know. He will be neutral.

This is the only story that really matters from the second leaders’ debate. Corbyn will hope that his gesture of impartiality will be seen as his contribution to the Brexit-healing process. But entering into negotiations with the UK’s European partners to impress upon them a deal that he won’t personally recommend is not the stuff of hardball diplomacy. 

No sooner had the show gone off air than the Foreign and Health Secretaries, Dominic Raab and Matt Hancock, toured the Spin Room to try out on the assembled journalists the Tories’ scripted response that Corbyn’s indecision would be final.  As Hancock put it, “Jeremy Corbyn has abdicated responsibility on the greatest issue facing the country.”

That may prove a telling claim. But only if by 12 December voters are still convinced that this is an election, first and foremost, about “getting Brexit done.”