Australia secured a 4-0 series victory as England’s miserable Ashes campaign came to an end with a comprehensive innings and 123-run defeat on the final day at the SCG.

Needing six wickets for victory, Steve Smith’s side’s chances were boosted when Joe Root failed to resume his innings at the start of the play after being treated in hospital because of a viral gastroenteritis bug.

The England captain did appear an hour into play after Moeen Ali was dismissed by Nathan Lyon (3-54) for the seventh time in the series, and he showed plenty of courage, going on to score his 37th Test half-century.

However, he could failed to reappear after the interval and the tourists subsided in quick time, finishing 180 all out as Pat Cummins took 4-39 to complete Australia’s rout by mid-afternoon.

Starting the day still 210 runs short of making Australia bat again and needing to bat the full day to salvage a draw, England’s chances were severely hampered when Root, who was 42 not out overnight, didn’t come out to start his innings.

Moeen survived for almost an hour in Root’s initial absence until he fell for the seventh time in nine innings this winter to off-spinner Lyon, trapped lbw for 13.

Having arrived at the SCG after suffering from severe dehydration, diarrhoea and vomiting overnight, Root entered proceedings to a standing ovation and he quickly turned his unbeaten 42 into a 130-ball half-century.

Alongside Bairstow, Root battled hard to guide England to lunch without further loss and with the pair established at the crease there was just a glimmer of hope that the pair could perhaps pull off a remarkable stalemate.

However, Root, who was visibly struggling before the interval, was once again absent with the effects of his illness and England soon lost Bairstow, who kept out 142 balls for his 38, lbw to Pat Cummins.

Stuart Broad was the next man in and his innings lasted just two balls as Cummins struck for the second time in the over, the England seamer fending a short ball to Tim Paine.

There was still no sign of a Root return as Australia took the second new ball and England’s Ashes rear-guard was coming to a quick end as Cummins bounced out Mason Crane on his way to an eight-wicket match haul on his home ground.

Josh Hazlewood had the final word on the series, striking the final blow when James Anderson was caught-behind fencing at a short ball as Root decided against batting again.

All that was left was for Smith and his side to get their hands on the Ashes as deserved winners of what was a hugely one-sided series.

- Sky sports