'You're sitting next to a turkey!': Cameron ridicules Miliband over warning Ed Balls has nine months to save his job Shadow Cabinet insiders insist Miliband can be 'ruthless' with whole team Balls under pressure after dismal performance at the Autumn Statement He turned red and lost his way while colleagues looked uncomfortable Shadow Chancellor has until party conference in September to improve By Jason Groves and Matt Chorley Ed Balls was today branded a 'turkey' after it emerged he has been given nine months to save his job following a series of dismal performances. Ed Miliband is weighing up whether to sack his Shadow Chancellor amid internal criticism and polling evidence that he is damaging Labourâ€™s election chances. Today in the Commons David Cameron seized on the revelation, claiming Mr Miliband was 'sitting next to a turkey' who was too weak to fire. Joke: Within minutes of David Cameron branding Ed Balls a turkey, parody account @GeneralBoles posted this image on Twitter Ridicule: Ed Balls (left) was dismissed as a 'turkey' by David Cameron as he clashed with Ed Miliband (right) Mr Balls was Mr Milibandâ€™s third choice for Shadow Chancellor after his brother David turned him down and Alan Johnson quit. His red-faced performance in response to George Osborne's Autumn Statement led senior Labour figures to admit that their key economic message was not being well-sold. A Shadow Cabinet source said Mr Balls had until Labourâ€™s conference next September to come up with a credible economic plan or face the sack. â€˜Ed doesnâ€™t want to have to sack Balls because of the disruption it will cause, but if weâ€™re still in difficulty on the economy by conference then he will do it,â€™ the source said. â€˜You should not underestimate how ruthless Ed is. He will not let anything stand between us and the election, and that includes Ed Balls.â€™ Attack: Mr Cameron today dismissed Labour attacks on the government's economic policy, as employment figures showed a record 30million are now in work The source acknowledged it would be â€˜difficultâ€™ to remove Mr Balls because of his powerbase in Labourâ€™s Brownite camp and the trade unions, and his wife Yvette Cooperâ€™s position as Shadow Home Secretary. But the source insisted that Mr Balls would come under intense pressure to knuckle under rather than destabilise Labour in the run-up to the 2015 election. â€˜Yes, it would be difficult, particularly with Yvette. But Balls could not afford to cause too much trouble nine months out from an election â€" the party would never forgive it.â€™ 'You don't need it to be Christmas to know when you are sitting next to a turkey' David Cameron on Ed Balls At Prime Minister's Questions, Mr Miliband and Mr Cameron clashed over unemployment figures and the impact on family finances. But as Mr Balls, sitting next to Mr Miliband, started gesticulating across the despatch box, Mr Cameron hit back: 'Ah! We have a new hand gesture from the shadow chancellor. 'I would have thought after today's briefing in the papers the hand gesture for the shadow chancellor should be "bye bye." 'You don't need it to be Christmas to know when you are sitting next to a turkey.' There has been speculation that the former Chancellor Alistair Darling might be tempted to return after he has finished leading the campaign to keep Scotland in the Union next autumn. One Labour source said: â€˜Alistair Darling is an option. But people putting it forward forget that Edâ€™s big picture message is that we have moved on from the last Labour government. Alistair doesnâ€™t fit with that.â€™ Other possible successors include the shadow business secretary Chuka Umunna, the shadow work and pensions secretary Rachel Reeves and the shadow foreign secretary Douglas Alexander. Decision: Senior Labour figures say leader Ed Miliband will have to decide whether to keep Mr Balls in post in time for the 2015 election Tipped: Shadow business secretary Chuka Umunna (left) and shadow work and pensions secretary Rachel Reeves are seen as possible successors to Mr Balls Mr Balls â€" who wrongly predicted the Coalitionâ€™s economic plans would cause a triple-dip recession â€" has come under intense pressure in recent months as the economic recovery gathers pace. An opinion poll at the weekend showed that although Labour retains an overall lead, just 21 per cent trust the party on the economy, compared to 32 per cent supporting Mr Osborne and Mr Cameron. â€˜You should not underestimate how ruthless Miliband is. He will not let anything stand between us and the election, and that includes Ed Balls Senior Labour source Senior Labour figure are concerned that Mr Ballsâ€™s strident criticism of the Governmentâ€™s deficit reduction programme will come back to haunt them if the recovery takes off. Mr Balls has spent the last three years talking down the economy, predicting a triple-dip recession and the loss of one million jobs â€" and warning that Government cuts would â€˜choke off â€˜ the recovery. Mr Balls sparked derision in the Commons earlier this month when he accused the Chancellor George Osborne of being â€˜in denialâ€™ about the economy. The crimson-faced Shadow Chancellor stumbled on, but his performance led to fresh questions about whether he was now an electoral liability. One Labour MP said he had â€˜f***ed upâ€™ Labourâ€™s economic policy by refusing to change course despite overwhelming evidence that the recovery is underway. In an angry response Mr Balls insisted he didnâ€™t â€˜give a t***â€™ about criticism of his performance. David Cameron mocked him in the Commons last week, saying the pugnacious Shadow Chancellor â€˜can dish it out, but he canâ€™t take itâ€™. Ominously, Mr Miliband laughed openly at his Shadow Chancellorâ€™s discomfort when Mr Cameron suggested his career was â€˜going downâ€™. Tensions between Labourâ€™s top two emerged last month when a leaked email from one of Mr Milibandâ€™s senior aides described Mr Balls as a â€˜nightmareâ€™. Shadow Cabinet ministers are also braced for a series of bruising encounters with Mr Balls in the New Year as Labour tries to hammer out its manifesto position on key issues like education and health reform. Blairite figures warn that Mr Balls is a â€˜roadblockâ€™ to reform, and still wants to keep an iron grip on public services from the centre, rather than devolving power and tailoring services to users.