Embattled Labour leader, Jeremy Corbyn, has said that the claims made by his deputy leader, Tom Watson, that the party is being infiltrated by a Trotskyist entryist movement are "nonsense". Alongside those comments, Corbyn said that he was "very disappointed" by the news that the High Court's decision to allow Labour's new members to vote in the upcoming leadership election had been overturned by the Court of Appeals.

In an interview with the Observer, Corbyn said he'd ask Watson to "do the maths". "300,000 people have joined the Labour party – at no stage in anyone's most vivid imagination are there 300,000 sectarian extremists at large in the country who have suddenly descended on the Labour Party."

"Sorry Tom, it is nonsense," said the Labour leader, "and I think he knows it's nonsense".

Watson had previously said that though he does not think the majority of Labour's new members are formed, or are influenced by, the militant left "a small group of Trotskyite activists have taken leading roles in the Labour Party or are seeking to do so".

"They are also explicitly targeting Young Labour and Labour student clubs with the aim of recruiting new members," said Watson. "That is beyond dispute. We can't deal with this problem until we acknowledge it exists."

In this weekend's interview, Corbyn said that he did not think the new members being allowed to vote would affect the result but that he thought "people should have the right to take part and that is surely what democracy is about".

When asked whether he thought there was any entryism, he replied: "I haven't noticed it and I have met very large numbers of new members".

After being asked several times, Corbyn also did not express 'full confidence' in Iain McNicol, General Secretary of the Labour Party, and said that the party's National Executive Council "will no doubt ask him questions and he will give answers on it".