"Let's quote from Mao," John McDonnell unexpectedly said from the Commons Despatch Box on Wednesday afternoon - to the delight of George Osborne and horror of some Labour MPs.
The shadow chancellor produced the Chinese communist leader's Little Red Book of speeches from his pocket in order to help Osborne in doing business deals with Beijing.
"I never envisioned when it came to nationalising I would be outdone by a conservative chancellor," McDonnell told MPs as he responded to the chancellor's Autumn Statement. "I would like to bring services like rail back into ownership of the British people. The chancellor wants to sell the to the People's Republic of China."
He added: "Nationalisation is OK for him as long a it is by any other state but ours."
"To assist comrade Osborne in his dealings with his new found comrades, I’ve brought him along Mao's Little Red Book."
Quoting from the book, McDonnell read: "We must learn to do economic work from all who know how, no matter who they are. We must esteem them as teachers, learning from them respectfully and conscientiously. We must not pretend to know when we do not know."
Osborne, who is desperate to paint McDonnell and Jeremy Corbyn as far-left, could not believe his luck. "The shadow chancellor literally stood at the Despatch Box and read out from Mao's Little Red Book," he said with glee. "It’s his personal signed copy."
Noting divisions between Corbyn and several senior Labour MPs, the chancellor added: "The problem is half the shadow cabinet have been sent off for reeducation."
"People treat this Labour leadership as a joke. They are actually a deadly threat to the economic and national security of this country."
Chris Leslie, Labour's last shadow chancellor, told the Commons he was "more interested in the wisdom that is contained in the Big Blue Book from the Office for Budget Responsibility" that details figures from the Autumn Statement.
And Labour MP John Woodcock, who is no fan of the current party leadership, appeared less than impressed.
Conservative MP James Cleverly claimed MPs rushed to the House of Commons library to snap up copies of the Little Red Book.