Nasser Hussain says turning England's fortunes around will be the biggest challenge of Alastair Cook's career.
But why has his side gone from Ashes holders to Test match folders and should the manner of their defeat be a complete shock?
Sky Sports pundits Mike Atherton, Nasser Hussain, Bob Willis, Shane Warne and Sir Ian Botham reflect on England's slump and Australia's dominance...
How have England fallen so far, so dramatically?
ATHERS: I suppose there were signs in England that Australia were prepared to play some competitive cricket. England won 3-0 at home but a lot of those Test matches were very close and if we are saying that poor batting has been the principal reason for England's decline here then you can go back to that series and look at how Australia bowled to Alastair Cook, the way they started to undermine Jonathan Trott with the short ball and how Matt Prior's batting form declined.
After Trent Bridge Jimmy Anderson got his wickets at about 48 runs apiece and that has continued through to this series. Australia neutered Graeme Swann in this series by picking a lot of right-handers in the middle-order and adopting a strategy to attack him. They began to undermine a lot of England's key players in that series. Most of us predicted a very tight series but the dramatic nature of the turnaround has surprised everybody.
SHANE: Australia caught England on the hop. As much as England will say they expected Australia to come out and play this aggressive style of cricket I think they took how well they thought they were playing for granted. The scoreline in the summer flattered England. Australia knew what their best side was by the end of the series and adding David Warner and Mitchell Johnson has given them some X-factor and some serious intent.
Why is there such a gulf between the teams?
NASSER: The main key is that Australia have dismantled the spine of this England team: Cook, the captain; Trott, their rock at number three; Pietersen, their star performer; Anderson, their swing bowler; Swann, their off-spinner; Prior, their wicketkeeper. The spine of the team has been dismantled. Any crumbs of comfort have come from the young lads like Joe Root and Ben Stokes.
SHANE: England's top-order players have let themselves down, particularly in the first innings, because it has been so hard for the England bowlers to come out and bowl and bowl and bowl pretty much every day.
NASSER: When confidence goes, it's very difficult to drag it back. You are always under the microscope. England players have come out here before in the past under Andrew Strauss and if anything all of the sledging from the local papers has been on their home team, who haven't been playing well. But since this team arrived here, they have been nailed - not only on the field but off the field too. You have to be very strong mentally to be able to cope with that. That's why someone like Ben Stokes came in fresh and just strolled his way to a hundred. Mitchell Johnson didn't play in the summer so he didn't have any mental baggage coming into this series.
SHANE: Australia's bowlers have been outstanding - they've hunted in packs and given no respite. Mitchell Johnson's delivery to Cook in Adelaide was a ripper, as was Harris' to Cook in the second innings here. That was an absolute 'jaffa'. That shows the mind-set and the intent. They are aggressive and I think Michael Clarke has to take a lot of the credit for saying 'this is the brand of cricket we're going to play'. The players have believed in Clarke and played that way. There's no fear and I think that's to be admired.
Can Alastair Cook turn things around?
NASSER: Australia is not an easy place to come and win. Sides and captains before Alastair Cook have come out here and struggled and he's got a couple of very good deliveries, but that's the way the game jumps up and bites you in the backside. So as a batsman and off the field to a degree, I sympathise; on the field, he has made a couple of glaring errors. In the first innings here his bowling attack suddenly started to bowl half way down. The very next day when the bowlers got the line and the length right, he was setting two slips and a gully and a third man when everyone knows at the WACA that a lot of catches go in that slip cordon.
So he's made errors but he's a young, learning captain. I still believe he's the best man for the job but this is now the hardest time of his career. England are 3-0 down. Australians want 5-0. His game is struggling; he's got bowlers all over him like a rash. He's got an opposition captain that is out-captaining him. He has often in the past come back in these situations but this will be the toughest for him.
ATHERS: Cook can look at this as a fantastic opportunity. He basically inherited Andrew Strauss' side but it is clear that side is coming to the end of its time. We don't know how quickly the selectors will change but he can view this as a fantastic opportunity to build a side of his own. There are 14 Tests before the next Ashes in 2015.
BEEFY: I agree. If you are going to take something from this result and try to look to the future, it gives Alastair Cook a chance to remodel the side so it is his side. He inherited a very good side from Strauss but that might give him some incentive and something to look forward to because he's got to find something to get him going because the cricket hasn't helped. Maybe that's something for him to think about and maybe Ben Stokes will fit into that future planning.
Should England ring the changes?
BOB: I'd put Root back in the opening position because Michael Carberry is not the future. Ian Bell has taken over from KP as England's best player so I want him to bat in the very important position of No 3. Gary Ballance is someone who deserves a debut but Matt Prior is in the worst form he's been in since he was left out when England were in Sri Lanka a number of years ago. I'd put Ben Stokes down to No 7 because he would bowl more overs in this team and I've also left Graeme Swann out. I think Monty Panesar would go better against the Australia right-handers in the middle-order. There is a case for resting James Anderson too, but to throw in both Steven Finn and Boyd Rankin might be a step too far, so I'd go with Steven Finn and we hope that Stuart Broad will be fit for Melbourne.
NASSER: I'm not here to back up senior players - senior players have underperformed and none of them will have a leg to stand on if they are left out. Are England a better side if Gary Ballance or Kevin Pietersen is walking out at Melbourne? Who would Australia prefer? I still see Pietersen as a threat, I still see him as a world-class player, just as I still see Alastair Cook as a threat. These guys have earned a little bit of leeway and time.
ATHERS: With Pietersen it's a question of productivity, mainly. I'm a little bit sick and tired of talking about the way Pietersen plays. The bottom line, whether aggressively or defensively, is how many runs you get. The bottom line for Pietersen and the rest of the batsmen in this series is they haven't been productive enough. Is he after 100 Test matches still as hungry as he was? If I had one criticism of Pietersen it would be that over the last year or so - maybe 18 months - I'm not quite sure how much batting in the middle he's had. He tends to pick and choose the cricket that he plays and that tends to be Test matches, where he wants to find his form. That's fine but if it doesn't go right you have nowhere else to go. I think he's been a little bit caught out by that.
Watch highlights of today's play on Sky Sports 2. The Ashes Verdict returns tonight at 9pm. Join us for live coverage of the fourth Test on Boxing Day.