John McDonnell, Labour’s shadow chancellor, welcomed the financial crash that wrecked Britain’s economy and insisted he was a Marxist, newly uncovered footage shows.

Mr McDonnell, who is Jeremy Corbyn’s closest political ally, is seen in the 2013 video saying that the economic upheaval proves the faults with modern capitalism.

At one point Mr McDonnell, who was a backbencher at the time, says of the crisis: “I’ve been waiting for this for a generation!”

The comments are documented in a YouTube video viewed less than 60 times which was posted on the website on March 16, 2013.