John Bercow has unleashed what was arguably his most brutal attack on a minister yet, after he dressed down the defence secretary and branded him "utterly incompetent".
The humiliating moment for Philip Hammond, which will only worsen the already strained relations between Bercow and the Tory benches, came after he arrived in the Chamber to make a statement on army reserves but failed to provide related documents.
"The content of statements is not a matter for me and I take no view of them but the administration of this matter has been woefully inadequate and frankly utterly incompetent. I've not known a worse example during my tenure as Speaker," Bercow said.
"Although you have expressed yourself in your usual understated terms, I hope you genuinely do feel some sense of embarrassment and contrition at what has been a total mishandling by your department, for which you are solely responsible. It's as simple as that."
Hammond, who is widely tipped to be positioning himself for a leadership challenge in the future, apologised to the Speaker.
"First of all I am indeed embarrassed by what appears to have just occurred and as you would expect I will be investigating precisely what has happened and I will write to you to let you know what has gone wrong this afternoon.
"I understood that copies of the statement and copies of the spreadsheet would be distributed as soon as I sat down. I apologise that did not happen."
The altercation comes just a day after Bercow was involved in a bad-tempered exchange with the prime minister over the private member's bill for an EU referendum.