Australia have fought back in stunning fashion in the middle session on day two, with Mitchell Johnson and Nathan Lyon seizing control away from England in the first Test at the Gabba.
Spinner Lyon took two wickets in successive balls and comeback kid Johnson had four with England reeling at 8-94 at tea.
England lost 6-9 in a blistering capitulation which made Australia’s first innings total of 295 look substantial.
The tourists still require a run to pass the follow-on, trailing by 201 after at one stage looking solid at 2-82.
Opener Michael Carberry made 40, but no other England batsman has passed 18, with the Ashes holders falling into all the traps laid out by Australian captain Michael Clarke.
Harris (2-25) and Johnson (4-46) took care of the England top four, but the match really turned on its head when much-maligned off-spinner Lyon had run-machine Ian Bell caught by Steve Smith at short-leg.
On the very next ball it was deja vu, with Smith flying to his right from bat-pad to nab Matt Prior, who had clearly nudged one onto his pads.
Stuart Broad, who was the third victim in Peter Siddle’s hat-trick at the Gabba in 2010-11, came into a chorus of jeers with the score at 6-87.
Lyon (2-7) muffed the hat-trick ball, but in the next over the jubilation returned when No.6 Joe Root became Johnson’s third wicket, edging to the slips to give Smith his third successive catch.
Lyon and Johnson might have turned the knife, but it was Harris who started the ball rolling when he removed Alastair Cook for 13, just when England’s openers looked to be getting set.
Then after a less than auspicious start, Johnson returned to the attack with the specific job of exposing Trott’s weakness against the short ball.
He had immediate success and Trott was back in the pavilion on the last ball before lunch, after edging down legside to Brad Haddin.
In his 50th Test, it was Haddin’s 200th dismissal, with his superb 94 powering Australia back from their own collapse where they were at one stage 6-132.
Harris celebrated the key wicket of Kevin Pietersen in his 100th Test to make it 3-82, and from there the flood gates opened.