Labour has dismissed Lord Mandelson's claim that 30,000 Labour members have quit the party under Jeremy Corbyn's leadership as "way off".
Speaking at a gathering of Labour Party leaders and peers in the House of Lords, the Labour peer said "two parties" were developing under Mr Corbyn - one of moderate members and another of the leader's own supporters.
He told a gathering of Labour party leaders and peers in the House of Lords: "30,000 long term members have left the Labour party, real members of the Labour family, tens of thousands.
"There are now two Labour parties."
He asked the Labour leader: "What are you going to do about it? How are you going to reach out?"
Lord Kinnock, who served as Leader of the Opposition from 1983 to 1992, asked Mr Corbyn to confirm he would resist attempts to introduce "mandatory reselection", which would see MPs reapply to local members to keep their posts.
In his reply, Mr Corbyn insisted the party was now more "vibrant" than ever before, adding "I condemn abuse" and said he welcomed "open debate".
A Labour Party spokeswoman declined to comment on membership numbers.
However, in October Labour said its statistics showed 183,658 people had joined the party since the May 2015 election, bringing the total membership up to 370,658.Reuse content