Jeremy Corbyn's critics could be welcomed back into the shadow cabinet if he wins the Labour leadership contest, his allies have said.

Shadow chancellor John McDonnell said he would like to see Labour leadership challenger Owen Smith return to the top team, while shadow foreign secretary Emily Thornberry said MPs "owe it to the Labour Party to work together".

However, Thornberry also suggested that shadow cabinet ministers could be elected by the whole of the Labour Party - potentially strengthening the position of Corbyn's allies because of the leader's popularity with the grassroots.

Despite Owen Smith's insistence that he can win the leadership when the results are announced on September 24, Corbyn is favourite to retain his position.

Shadow chancellor John McDonnell said he would like to see Owen Smith return to the shadow cabinet. Credit: PA Wire

This has sparked speculation that many of the senior MPs who quit shadow cabinet roles could seek a return to the top team.

Earlier this month, Labour MPs and peers supported proposals to restore elections to select the shadow cabinet in a move viewed as a renewed challenge to Corbyn, who marks one year as party leader on Monday.

The Parliamentary Labour Party held a ballot on reintroducing the measure Ed Miliband scrapped in 2011 to give him a free hand selecting his senior team.

But the vote is not binding, and the reform will need the backing of the ruling National Executive Committee and the party's conference before it can be introduced.

Thornberry told BBC Radio 4's Westminster Hour: "I think that the process of opening the party up to democracy and working with this enthusiasm is a good thing.

Shadow foreign secretary Emily Thornberry urged Labour MPs to work together. Credit: PA Wire

"If we are going to have shadow cabinet elections then I think it is something we should think about.

"If we are going to have them elected, maybe we should be thinking about party conference or the membership having some sort of input into that. Why not? What are we afraid of?"

The shadow foreign secretary urged colleagues to unite behind Corbyn, but conceded that there are "certain people who have very hardened positions and who will not work with Jeremy".

Thornberry added: "But I think there are many others who will accept democracy within the party and who will work to do the best they can for the sake of the Labour Party, because the Labour Party is bigger and greater than all of us, we stand on the shoulders of giants. We owe it to the Labour Party to work together."