Nick Clegg may be batting his eyelashes at Labour, but he won't turn a cold shoulder on the Tories

Nick Clegg plays an unusual role in British politics. His personal ratings are dire, and yet he remains a very big player. The last few days are typical. On Friday morning, he woke up to headlines reporting that his party had lost its deposit again at a by-election. In contrast, yesterday Clegg was greeted by newspaper front pages implying that he will be the pivotal figure after the 2015 election, perhaps in coalition with Labour. One moment his party is slaughtered, the next he is contemplating another five years in power.

The sequence is typical. During the last election, Cleggmania was the only memorable event of the campaign. Within months, he was the most loathed public figure in Britain. For a leader who claims to be in the steady centre, he must be getting used to extreme highs and lows.

His warm-ish words about Labour and his unequivocally critical comments on the Conservatives come from a series that I am presenting for Radio 4 on Clegg’s extraordinary career. At the end of a long interview I asked him whether he constantly viewed the other parties in terms of being potential coalition partners. He said that as a pluralist he inevitably did, before the last election and now. I then asked him what he thought about Labour and he noted what he saw as an encouraging change of approach in its attitudes towards him and his party. In relation to the Conservatives he was much harder, observing a marked shift to the right. With some justification, the words have been interpreted as Clegg opening the door to a coalition with Labour.

But there is a very big qualification. Clegg has secured agreement across the Lib Dems for his consistently held line that in a hung parliament he would feel obliged to negotiate with the biggest party, Labour or Tory. Every Lib Dem I interviewed for the series repeated this position. Some senior figures do not believe that another Con/Lib coalition will be possible, even if Clegg embarks on another set of negotiations with Cameron. Nor do I, for reasons I set out in a column last month. This is not Clegg’s view. If the Conservatives were the biggest party again he would turn to Cameron first to explore the possibility of another coalition.

Nonetheless, in my interview with him he chose to be more positive about Labour. Paddy Ashdown tells me that, during the frenzied five days after the last election, Clegg sought to reassure him that Cameron and his allies were a new type of Conservative. Evidently Clegg almost believed Cameron’s claim that he was a "progressive". The Lib Dem leader is less sure now, and he knows that the rest of the Conservative party is not for changing, even if Cameron were inclined to challenge his MPs and activists, which he is not.

The Labour peer, Andrew Adonis, has written a compelling book on those five days after the last election in which he argues that Clegg is a Conservative who always wanted to deal with Cameron. Ashdown is adamant that that is not the case, and that Clegg was “tortured” at the prospect of a coalition with the Tories. I suspect that Ashdown is closer to the truth on this. He is the only former leader with whom Clegg remains in regular contact and he is still a very big influence. The clash of interpretations arises because Clegg is a different type of Lib Dem leader. I asked Ashdown whether Clegg was on the centre left. He replied without hesitation: “yes”. When I told Clegg that this was Ashdown’s view of his politics, he did not fully concur, preferring the term “liberal”. He is the first leader of his party for decades who does not describe himself without qualification as being on the centre left.

The key issue in any future negotiations for a coalition is the precise context in which they take place, not Clegg’s politics. Clegg tells me that, in 2010, contrary to mythology, he was depressed because his party had lost seats. He read and heard all the time that he was on a high as the mighty power-broker. But he did not feel remotely euphoric, having hoped to make gains at the election. Because of this context, Clegg underestimated the strength of his negotiating position, given that Cameron/Osborne ached to become PM and Chancellor. At the very least, he should have ruthlessly vetoed policies that have subsequently caused him near-fatal trouble.

After the next election the opposite might well apply. Clegg could feel stronger – in that he will be incomparably more experienced – and yet be much weaker. Last week’s by-election shows how vulnerable his party still is, in spite of the formidable victory in Eastleigh a year ago.

As a commentator, I cannot see how another Con/Lib coalition is secured, but struggle almost as much to envisage a Lib/Lab coalition forming smoothly, with Labour pledged to reverse some public-service reforms that Clegg supported, and still supports, and with a subtly different approach to the deficit. As leader of the third party, and from a background in Europe, Clegg can envisage a partnership with either.

Alex Salmond’s biggest weapon in the referendum campaign is England. Parts of England might not appreciate the degree to which a right-wing consensus has taken hold since 1979, but in social‑democratic Scotland, most voters know only too well. With justification, they want to keep their distance.

This does not mean that a majority of them want independence, but it does suggest that the tone of the interventions from English public figures needs to be very carefully calibrated.

The tone must be humble if it is to resonate. Quite a lot of the undecided voters in the referendum already believe that English public figures are lofty bullies, therefore there are more dangers than gains in playing hardball on the currency. The arguments of George Osborne, Ed Balls and co are potent, but they reinforce a view about England rather than challenge it.

The referendum is one of the most bizarre contests in modern times. David Cameron called it, but cannot campaign extensively in case he loses votes rather than gains them. The same applies to most ministers at Westminster. This means that any powerful arguments from England that take the form of a warning to Scotland can be counter-productive.

Every utterance from an English politician should be preceded by a sequence of ruthless calculations: how would undecided voters expect me to behave, and what can I say to challenge that stereotype?

This is not easy because it calls on English politicians to downplay some arguments, another reason why it is an odd and unpredictable campaign.

@steverichards14

Nick Clegg: The Liberal Who Came To Power, is on Radio 4, Monday, 8pm