By Jonathan Agnew BBC cricket correspondent at The Oval

The weather has been kind to England and that, coupled with the new ICC regulation relating to bad light, increases the likelihood of Michael Vaughan leading the celebrations at the end of the match.

With 98 overs left there is still a possibility Australia could win Umpire explains bad light ruling

There is still more than enough time left for Australia to dismiss England and win the game themselves, but Ricky Ponting's team were denied the extended opportunity they needed by the re-wording of the bad light regulation.

It used to be the case that the batsmen had to be in physical danger in order to be offered the opportunity to leave the field.

That enabled the fielding captain to bowl his spinners at each end, and play would continue.

Now it is merely a case of there being the need for a balanced contest between bat and ball.

If that, in the view of the umpires, is compromised by the conditions, they ask the batsmen if they want to continue.

Bad light has always been a contentious issue, basically because it suits one team to go off, and works against the other.

These days, when the umpires decide the light is bad, they offer it to the batsmen and take a reading with their light meters.

Whatever that reading is - and it varies from ground to ground - it is used as a benchmark for both teams throughout the match.

It eliminates disputes amongst the players - but spectators can still be forgiven for feeling that it is a cynical exercise and that the same team will choose to stay at the crease one day, and come off the next.

Flintoff prevented Australia taking a first innings lead

Although the bad light ruined the fourth day, it was preceded by a fascinating passage of play.

As England bowled Australia out, led magnificently by Andrew Flintoff, the realisation dawned that, in fact, this probably represented Australia's best chance of winning the game.

England suddenly found themselves batting under intense pressure and when Shane Warne dismissed Andrew Strauss with only his fourth ball, the reality of the situation hit home.

With 98 overs still left in the game and a much-improved weather forecast, there is still the possibility that Australia could win.

They would need to dismiss England within 60 overs, or so, to leave them a run chase to save the Ashes.

What a finish that would be to this amazing series.