Jeremy Corbyn is set to give his first major speech as Labour leader amid criticism from his union supporters over his choice of shadow chancellor. The left-winger has appointed long-time ally and friend John McDonnell to the key post, to the frustration of union activists as well as Labour MPs.
Corbyn will likely get a warm welcome as he takes to the stage of the TUC Congress in Brighton on Tuesday afternoon, after winning the support of many big trade unions in his leadership battle. But the backlash over his shadow cabinet – which has also been criticised for being too male – will carry on behind the scenes.
One senior union official told BuzzFeed News that McDonnell's appointment was a "terrible choice".
"He's a relic of the past and too hardline," the official said. "He's not exactly the world's greatest listener and doesn't take criticism well. It just sends out the wrong message."
McDonnell has previously argued for a 60p top rate of tax and nationalisation of the banks, and he lists "generally fomenting the overthrow of capitalism" among his interests in the Who's Who book of influential people.
Friends of Corbyn say he wanted someone he could trust by his side as shadow chancellor. They claim that because so few Labour MPs actually backed him as leader, Corbyn feels that he needs a close friend in the key role and a clear anti-austerity message to deliver – he doesn't want a shadow chancellor briefing against him.
But many activists fear McDonnell's selection was huge mistake. They believe Angela Eagle, shadow business secretary and shadow first secretary of state, would have been far better suited to the role.
Eagle, who was Treasury exchequer secretary under Gordon Brown, is seen as a much safer pair of hands. The union official said that as chair of Labour's National Policy Forum, she had proven she was able to discuss policy ideas sensibly and there would have been no danger of any Tony Blair and Gordon Brown-style splits.
One union member attending a TUC fringe meeting was also in despair at McDonnell's appointment. They told BuzzFeed News he was "too far left" of the party and would not appeal to the country at large. And they warned he "harboured resentments" and could rub people up the wrong way.
Even TUC general secretary Frances O'Grady has urged Labour to reach out "well beyond its own ranks". In what was interpreted as a warning against a shadow cabinet of left-wingers, she said on Monday that Labour must "have a higher collective purpose beyond that of any one individual, or any one constituency of interest".
But another union official said they believed McDonnell was trying to shun his "bruiser" image. "He was Corbyn's campaign manager and knows the election was won by being inclusive and consensual," they said. "That's how he will try and position himself now, although the mask may slip occasionally."
Corbyn will no doubt win over the crowd in Brighton, publicly at least, before he faces a very different kind of battle on Wednesday – his first Prime Minister's Questions.