If Angela Rayner and Keir Starmer are in an ‘arranged marriage’, it could be a very messy divorce

More ominous than the theme from Jaws was the moment’s hesitation when Angela Rayner was asked if she knew what her policy responsibilities would be if there were a Labour government.

“Well,” she said to Nick Robinson on the BBC’s Today programme. “The important thing is that I will be the deputy prime minister and I will be the deputy leader of the Labour Party.”

This part of the interview was only a minute or so long, in between questions about the two-child cap on benefits, clean air zones, trans rights and miscarriages of justice – all of which Rayner dealt with confidently and well.

But then Robinson turned to her relationship with Keir Starmer. Do you ever say no to him, he asked. “Of course, and Keir says no to me,” she replied. The emphasis seemed to be on him getting his way rather than the other way round.

She said that their relationship had “evolved”, and went on: “I often talk about it as an arranged marriage. We were both elected by the membership differently and independently. We work constructively together.”

What a fascinating series of sentences. She has used the phrase “arranged marriage” before, in an interview two years ago, but it wasn’t clear then whether she was talking about the distancing effect of lockdown rules, which meant that she and Starmer rarely met in person.

There was no doubt about her meaning this time, because she referred to her own independent mandate from the party membership, as the unsackable deputy leader. This interview was a warning to Starmer that she means business, and that she has the power to cause trouble. It was a brief glimpse of the tensions behind the scenes that threaten the unity and purpose of a Labour government, long before it can be taken for granted that Labour will win.

There has been tension over whether Starmer would make her deputy prime minister if he formed “His Majesty’s Government”, as Rayner put it. There had been speculation that Starmer would withhold the title, as Gordon Brown did from Harriet Harman, deputy leader of the party when he was prime minister. Rayner has now laid claim to it so emphatically that it would be a declaration of war for Starmer to refuse to give it to her.

But deputy prime minister could be a meaningless bauble unless Rayner is given a department to run and important policy responsibilities – hence Robinson’s question. Again, there have been tensions between Rayner and Starmer over her plan, as shadow secretary of state for the future of work, to give workers full employment rights in a job from day one.

The tensions have a personal dimension in that Starmer sacked Sam Tarry, Rayner’s partner, from his shadow ministerial post for giving an unauthorised TV interview after appearing on a rail workers’ picket line.

There is a lot more going on than is visible to the naked eye. I am told that Rayner wants Starmer’s job, which may not be unusual at the top of a political party, but also that she believes that she is going to get it, which is not so common. I understand that she thinks that, should Starmer fall, she would be best placed to win a vote of party members – although she must be concerned by the rise and rise of Rachel Reeves, the shadow chancellor, over the past year.

Rayner and Starmer have already clashed once, when he tried to demote her two years ago, after Labour’s defeat in the Hartlepool by-election. But he was at his weakest point then, and she emerged the victor, with a string of shadow ministerial titles as the spoils.

Now, with the aura of a 20-point lead in the opinion polls around him, Starmer carries all before him. All the sunflowers are turning to face the sunshine of an incoming prime minister. But there are limits to his power. One of them is Rayner, with her independent position as deputy party leader, her base among party members and the support of a significant group of MPs.

Another is Reeves, who has made herself unsackable by the admiration she has earned for her unflashy fiscal responsibility. It may be significant that differences opened up between Reeves and Starmer recently. She defended Alison Rose, the boss of NatWest, whereas Starmer condemned the bank’s subsidiary for closing Nigel Farage’s account. And Reeves took a harder line on the expansion of London’s ultra-low emissions zone, calling on London mayor Sadiq Khan to scrap it, while Starmer urged him only to “think again”.

The dark cloud may be only the size of a fist at the moment, but Rayner’s interview this morning was like a storm warning for an incoming Labour government.