A QUIRK of the Ashes is what you might call the retention factor: the fact that if you have them, all you have to do to keep them is draw the series.

Usually, this has an unbalancing effect, handing a further advantage to the stronger of the two teams. A few years ago, when Steve Waugh’s marauding Australians were walking all over Nasser Hussain’s injury-ravaged Englishmen, it was the last thing the sport needed.

Now, however, it has become a good thing, and not only from a one-eyed Pom’s point of view. England go into this winter’s series in a curious position, as both holders and underdogs. Yesterday lunchtime, you could get 4-1 on England at several bookies, but no better than 2-5 on Australia. So the retention factor is helping the weaker team.

The ramifications of this are wider than they appear. In a five-Test series in Australia, history suggests that one match will be drawn, so there are four definite results to be shared. To get the Ashes back, Ricky Ponting’s team have to win three Tests. To hold on to them, Andrew Flintoff’s men have to win only two. That is a big “only”. Since Mike Gatting’s England managed it 20 years ago, just three touring teams have won more than one Test in a series in Australia, in each case West Indies in their daunting heyday. But winning two Tests should be more feasible this time. In recent home Ashes series, Australia have started well, bullying England from Day1. At Brisbane, traditional venue of the first Test, they haven’t lost to anybody since the Eighties, and for the past ten years, they have also been able to count on winning in Perth, where the third Test takes place.

But when England last encountered a Perth-like surface (hard, bouncy, at times frightening), against Pakistan at Old Trafford, they coped brilliantly. Brett Lee is always a handful at the Waca, but Flintoff and Stephen Harmison, if fit, will be two handfuls.

Adelaide, which hosts the second Test, has a flat pitch and short square boundaries, making it the most likely setting for the draw, so, after three Tests, there is a realistic prospect of the series being 1-1. Australia will then need to win the last two, given that draws at Melbourne and Sydney are rare. This is when the England supporters will be out in force, merrily chanting “5-0” whenever Glenn McGrath fields near them. Since the Barmy Army was founded, in 1994-95, England have always won one of the last two Tests — Adelaide that year, Melbourne in 1998-99 and Sydney last time.

The pressure will be on the Australians. With an attacking spinner in Monty Panesar, as well as tall fast bowlers to exploit uneven bounce, England are better equipped for the vagaries of Sydney than before. The itinerary is more welcoming this time, foregoing the pointless stint in Perth before the first Test 3,000 miles away in Brisbane. Australia are ageing, unprecedentedly so for them, and, to judge from Shane Warne’s dig at John Buchanan, their coach, and Ponting’s irate riposte, less than united.

Ponting is a central figure, not for his tepid captaincy but for his red-hot batting. England managed to contain him last summer, when he played only one decisive innings, salvaging a draw at Old Trafford. Since the Ashes, he has been a man possessed, with eight hundreds in 12 Tests. His average in home Tests over the past three years is an almost superhuman 86. If Duncan Fletcher’s plans can reduce him to mere-mortal status again, then even with all their injuries England have it in them to win two Tests.

Drawn five-Test series are strangely infrequent: the last one in the Ashes came in the see-saw summer of 1972. But that was the third in a decade. The law of averages, as well as English optimism, says that it is time for another.