It is understood Corbyn wants the party to speak with one voice on matters relating to defence and military intervention abroad after recent divisions, most notably over policy on Syria.
However, any attempt to remove either could result in a damaging conflict across the parliamentary Labour party and could result in resignations from the shadow cabinet, according to one shadow cabinet source.
Corbyn’s unilateralist and anti-military intervention beliefs were a key feature of his leadership campaign. Eagle is at risk because she is a staunch defender of Trident, while Benn’s position is being seen as problematic because he strongly supported military intervention against Islamic State in Syria after Corbyn spoke out against it.
The reshuffle is due in the new year, although claims that Monday 4 January has already been pencilled in as the day for it to happen have been discounted, as have claims that Corbyn has already decided to appoint Diane Abbott as the new shadow foreign secretary or to replace Rosie Winterton, the chief whip, with the Corbyn loyalist Jon Trickett.
The full scale of the reshuffle has not been decided. Corbyn’s main concern is said to be ensuring the party has a coherent voice on questions relating to the deployment of British power abroad, but he may well go further than just reallocating defence or foreign affairs. Corbyn accepts that his first shadow cabinet was put together quickly.
His allies also believe that the Labour split over foreign policy has overshadowed the extent to which the shadow cabinet is united on economic and domestic matters. John McDonnell, the shadow chancellor, recently said: “On domestic politics, there is virtually nothing between us [members of the shadow cabinet], absolutely nothing, other than some want to go faster than others.”
One party source said that Labour’s leader is receiving conflicting advice from his closest confidantes as to whether to launch a major reshuffle. “Some want to go all out for a hard-left agenda now. Others want to try and take the party with him. But if Benn or Eagle go [from the cabinet], others might follow,” the source said.
Another speculated that this might be the ideal time to bring back the former party leader Ed Miliband to the shadow cabinet. “Jeremy wants Ed back. If Ed was persuaded to return to energy, it would give an open the door to a reshuffle without all the focus being on the losers,” the party figure added.
Sources close to Miliband have downplayed any speculation that he might rejoin the shadow cabinet in January. A source close to Benn said he did not know of any plans for a reshuffle and has been concentrating on helping constituents whose lives have been devastated by the floods.
Corbyn is due back in the UK from a holiday in Malta and returned to a new analysis at the weekend suggesting Labour is making little progress under his leadership. According to the academics Colin Rallings and Michael Thrasher, the country’s most prominent local election experts, Labour has been performing poorly in local council byelections since Corbyn became leader in September.
There have been 60 such contests in England and Wales, according to the Rallings/Thrasher research published in the Sunday Times. Labour made four gains, but suffered three loses.
But Rallings and Thrasher say the picture looks worse when you consider the 27 byelections where a seat was being contested that was last contested in May, on the day of the general election. This allows a direct comparison with Labour’s performance at the election.
“Labour’s vote share was up in eight [of these 27 wards], but down in 19,” they write. On average, the Tory share in these byelections is unchanged; Labour is down by four percentage points; the Liberal Democrats’ share is up by seven and Ukip is fractionally down.
“While most of the byelections have not been in natural Labour territory, any downward drift compared with the general election is bad news and there is no evidence of a Corbyn bounce.”
But Rallings and Thrasher acknowledge that Labour is doing better in London under Corbyn. In the six council byelections in the capital since he became leader (seats last contested in 2014) Labour is on average up three points.
Rallings and Thrasher say, on current voting trends, they would expect Labour to lose 200 of the 1,200 council seats it will be defending in the May local elections.
This article was written by Andrew Sparrow and Rajeev Syal, for theguardian.com on Monday 28th December 2015 16.27 Europe/Londonguardian.co.uk © Guardian News and Media Limited 2010