IT is not only his England side that are falling further and further behind in this Ashes series.

Alastair Cook is also beginning to trail so far back in Australia that he might no longer be considered as the leading candidate to captain the team. The 29-year-old broached the subject of his future in the full glare of both a 4-0 series deficit and the Australian sunshine, with the only clouds forming over his capacity to lead.

He intends to continue in the role, although Cook might come to be removed from the picture should the Australians register a series whitewash in the fifth Test which begins on Friday in Sydney. The England captain was painted as a figure all out of ideas at the end of the fourth Test - which the hosts won by eight wickets - even if Cook gathered his resolve just in time to defend his team-mates for their performance. It is just unfortunate that they had not shown similar defiance as Chris Rogers (116) and Shane Watson (83no) completed Australia's fight-back from a first-innings deficit to once again trounce the tourists.

Cook would also defend the work being done by the coaching staff but they would perhaps be better served looking for cover. Both Graham Gooch and David Saker, England's batting and bowling coaches respectively, have become targets following their side's performances in the defeats Down Under.

It is a captain's prerogative to deflect blame away from colleagues even though it is a task which Cook acknowledges may be taken out of his hands by team officials.

"I'm 100% wanting to carry on," said Cook, who has been the England captain for little more than a year. "If someone makes that decision and says 'we think there's a better man' or 'you're not good enough to do it' then I have to take that on the chin because as a captain, you're responsible for the team.

"I'm fully supportive of our coaching staff. We've had some fantastic results . . . and it wasn't so long ago that we won in India with this same coaching staff [and also] against Australia with the same coaching staff."

Cook is determined to complete the series with a purposeful performance in Sydney and will be aware that the challenge of setting the momentum will fall to him as opening batsman. His tactics have been questioned by former captain Michael Vaughan, but he has also found cause to blame the indifferent displays of other senior players in the touring side.

"You've got guys who have played 100 Test matches in Kevin Pietersen, you've got guys like Stuart Broad," said Vaughan. "Why aren't they helping [Cook] out? Where are the coaches on the team? So far in this series, I don't think England's form, batting, bowling, fielding, planning or training has been anywhere near the standard of what I would expect from an England side."