A man has been found guilty of a knife attack on four officers who he had lured to a house with a fake 999 call.
Alex Traykov reported a fight at a house in Islington, north London, before unleashing "extreme violence" on the Met Police officers in October.
He was cleared of attempted murder, but convicted of three counts of wounding with intent and a fourth charge of attempted wounding with intent.
Traykov, 20, of Redhill in Surrey, will be sentenced on 10 May.
The court heard Traykov - who used the alias "Solomon" - lured officers to Liverpool Road on 6 October.
He then lay in wait with a large kitchen knife hidden behind his back in the hallway of his friend's flat.
Within three minutes, four constables arrived on the doorstep unprepared for the "extreme violence" about to be unleashed on them, the Old Bailey heard.
Prosecutor Duncan Atkinson QC told jurors: "Without hesitation or warning and certainly without the slightest provocation from the officers, he raised his right hand and proceeded to attack the officers."
Traykov brought the blade down on to the head of PC Istarlin Said-Ali, 31, cutting her hand as she warded off a second blow.
He lunged at PC Rafal Zedziora, 34, cutting his face and slashing the back of his neck.
Traykov went on to attack PC Ben Thomson, 40, before he was Tasered by PC Launa Watkins, 39.
The former Winchester University history student said he was so "high" on strong cannabis he was not thinking straight.
He claimed he had called 999 to play a "prank" on his friend then forgotten all about it and made crumpets with jam.
After his conviction, Det Insp Kate Stannard described Traykov as "a very dangerous individual" and said the attack was "frenzied and violent".
She added: "This case highlights the very real risk that police officers can be confronted with on a daily basis and the courage and professionalism officers demonstrate when doing their job."