Tony Blair has caused a stir by leaping into the election battle with a message of “100% support” for Ed Miliband.
The intervention of Labour’s most successful election-winner was welcomed by party strategists, but Conservatives mocked it as a sign of Mr Miliband’s “weakness”, while Ukip said they were pleased Mr Blair had drawn attention to their core message on Europe.
Former leaders tread a perilous tightrope when they re-engage with frontline politics, always caught between the twin dangers of appearing to complain at their successor’s deviation from their legacy, or of being seen as a domineering “power behind the throne” dictating policy.
Mr Blair has maintained a low profile in domestic politics since stepping down as prime minister in 2007, but his few pronouncements have been pored over for any signs of dissatisfaction with Mr Miliband’s stewardship of the Labour Party.
His comment in December last year that an election “in which a traditional left-wing party competes with a traditional right-wing party” would have “the traditional result” of Tory victory was widely seen as an attack on Mr Miliband’s departure from the centre-ground policies of New Labour.
But his endorsement of Mr Miliband in Sedgefield was far more enthusiastic than the backing he offered Gordon Brown when he made a clutch of low-key campaign appearances in the final stages of the 2010 contest and urged voters to judge Labour by their policies – widely seen as an implicit plea not to judge the party by its leader’s personality.
Even a staunch expression of support, however, could not prevent Mr Miliband’s political opponents looking for openings to use Mr Blair’s appearance as an opportunity to attack the Labour leader.
Tory chairman Grant Shapps described the deployment of the three-time election winner as “desperate”, while Conservative minister Priti Patel said: “It says a great deal that the Labour Party has got Tony Blair out today and that their own party leader Ed Miliband is nowhere to be seen.”
But to some on the left, Mr Blair’s presence was a sign that Mr Miliband had failed to distance himself enough from the legacy of New Labour. Radical party Left Unity said Mr Miliband needed to “ditch the toxic legacy” of his predecessor if he wanted to re-engage with disillusioned Labour voters.
Mr Miliband pronounced himself pleased with Mr Blair’s support, and revealed he had consulted with the former PM on policy during his leadership.
Compared with some other politicians, the Labour leader has had little to complain about in the behaviour of his predecessors.
Mr Brown has largely stayed away from Westminster, confining himself to high-minded commentary about international affairs and a decisive contribution to the Scottish independence debate, while Mr Blair has largely been absent overseas in his roles as Middle East peace envoy and globe-trotting confidante to the rich and powerful.
By comparison, Margaret Thatcher had to endure what was dubbed “the longest sulk in political history” from Sir Edward Heath, who was a glowering presence on the Tory backbenches for 26 years after being ousted as leader.
Mrs Thatcher herself promised not to be a “back-seat driver” to John Major, but was increasingly seen as a destabilising influence on her successor due to her encouragement of eurosceptic forces on the Tory benches.
She made a high-profile re-entry to the electoral fray in support of William Hague’s doomed bid for power in 2001, when she told a rally in Plymouth that she had seen a cinema billboard advertising “The Mummy Returns” and thought it was referring to her. Even then, her vow that she would “never” sign Britain up to the euro was seen as awkward for Mr Hague, who at that point was only ruling it out for the next Parliament.
But by that point she was 75 years old and her role was as a totem of past glories, not an active participant in current policy debates.
Mr Blair’s speech, by contrast, has dominated election coverage for a day and thrust the issue of Europe to the forefront of the campaign, in a sure sign of his continuing ability to seize hold of the political agenda.