John McDonnell has said that Boris Johnson’s refusal to rule out proroguing parliament threatens “the very nature of our democracy.”

The Shadow Chancellor joined some 160 MPs in signing the Church House Declaration, which commits MPs to using “whatever mechanism possible” to stop no deal. Speaking at Church House, McDonnell said: “I just give this warning to Boris Johnson. Prime Ministers come and Prime Ministers go, but actually I don’t think we’ve ever seen a Prime Minister like this who has the potential to threaten the very nature of our democracy.”

He added: “And I just warn him that we will not stand aside and let that happen. And exactly as the declaration says we’ll use whatever mechanism to prevent that happening – to secure the democratic rights of our constituents to be heard through their MPS, but also to secure the future of our country against such a reckless act.”