Even by the plummeting standards of recent prime minister's questions, today's session was dire.
Halfway through another achingly poor exchange between Cameron and Miliband, a man threw a bag full of marbles at the thick glass screen separating the public from MPs.
The collision was audible from the press gallery opposite, although his kicks and shouts of "answer the fucking question" as he was bundled out of the chamber failed to make their way through.
Whether this was a planned act of political protest, a metaphorical cry for help, or an understandable human reaction to the pitiful spectacle of today's exchanges is not clear.
Either way the small cracks the marbles made in the glass screen will probably have as much impact on the future of British politics as anything David Cameron or Ed Miliband said today.
Miliband began the session by asking David Cameron about his management of the NHS in England.
This was all reasonable enough. As Miliband later made clear, Labour plan to put the NHS "on the ballot paper" during next year's general election campaign and the prime minister can hardly expect to avoid questions about the health system during an election year.
David Cameron however had other ideas. Instead of answering questions about the NHS in England (which he is in charge of) he decided to answer by asking Miliband questions about the NHS in Wales (which he isn't in charge of.)
No matter what question Miliband asked, Cameron replied by asking the Labour leader about Wales instead.
It was like a particularly unfunny cross between the Two Ronnies Mastermind sketch and the American gameshow Jeopardy. With every question that went unanswered the Labour leader became visibly more frustrated while the prime minister became visibly more smug.
If the man in the public gallery hadn't had a bag of marbles to hand, he could have been forgiven for propelling his own face into the glass screen instead.
Asked by reporters why he had chucked his bag of marbles at the screen, the unidentified man told reporters outside that he had "no comment mate".
If only Cameron and Miliband had been equally brief today, we could have all saved ourselves a lot of trouble.