Vaughan tries to keep it up tempo

England enter next week's Ashes decider against Australia with captain Michael Vaughan warning his vibrant and dynamic side of the dangers of allowing their levels of performance to drop.

Vaughan and his England team are on the brink of making history at the Oval next week, knowing anything but defeat in the final npower Test will ensure an historic first Ashes success since 1987.

They have dominated the last three Tests at Edgbaston, Old Trafford and Trent Bridge with their aggressive tactics to such an extent that Australia's once great line-up appears ripe for the taking.

But Vaughan is determined complacency will not creep into England's preparation for their biggest match in decades and will warn his side to beware an Australian side still capable of mounting a last attempt to retain the Ashes.

"It's difficult to say how far we've come or if we can play better because we have played so well," admitted Vaughan.

"We're very happy with the level of our performance that we've put in, but we realise we can't afford to drop from that."

With that in mind, Vaughan and England's selectors will be desperate for Simon Jones to recover from the right ankle problem he sustained during last week's thrilling three-wicket fourth Test victory in Nottingham.

Oxygen tent treatment

Jones has been receiving regular oxygen tank treatment, which is supposed to speed up recovery, in a desperate attempt to retain his place in England's unchanged line-up for the eagerly-awaited finale.

The Glamorgan seamer has contributed 18 wickets to the series so far and has provided useful variation to the different bowling styles provided by all-rounder Andrew Flintoff, Matthew Hoggard and Steve Harmison.

Should he fail to recover in time, however, England's selectors intend to leave their deliberations until they have monitored the big match temperament of Chris Tremlett.

The Hampshire seamer was selected for today's C&G Trophy final against Warwickshire at Lord's and the selectors will study his display before making any final decisions about the make-up of the squad, which will be announced tomorrow morning.

The selectors' other alternatives ahead of tomorrow's squad announcement are to call-up all-rounder Paul Collingwood, who scored a century for Durham this week, or consider a possible recall for Andrew Caddick two years after his last Test appearance.

"The way we've gone about our cricket is by having five bowlers and a varied bowling attack," explained Vaughan.

"We need those options when we play good teams, but who is to say we will not change that at the Oval - we'll have to look at the conditions and see who is bowling well and who we can bring in."

Possible England squad: MP Vaughan (Yorkshire, capt), ME Trescothick (Somerset), AJ Strauss (Middlesex), IR Bell (Warwickshire), KP Pietersen (Hampshire), A Flintoff (Lancashire), GO Jones (Kent, wkt), AF Giles (Warwickshire), MJ Hoggard (Yorkshire), SP Jones (Glamorgan), SJ Harmison (Durham), CT Tremlett (Hampshire).