Peter Siddle and Ian Bell had shocks in store for their Ashes opponents on day one of this winter's battle for the urn.

Siddle will never forget his hat-trick on his 26th birthday, as England were bowled out for 260 after choosing to bat first.

But this may just go down too as the day when Bell, two years Siddle's senior, at last came of age.

England's number six had to watch from the non-striker's end as Siddle finally ousted his fifth-wicket partner Alastair Cook (67), and then blew away the scoreless Matt Prior and Stuart Broad with full-length pace.

Warwickshire batsman Bell completed a deserved 50 soon afterwards and finished with eight high-class boundaries in his 131-ball 76.

It was a fine hand from a vastly improved cricketer, on a day which started on an ominous note for England when captain Andrew Strauss cut the third ball straight to gully for nought - and ended on a downer too after Graeme Swann was dispatched for successive fours in his solitary over in Australia's 25 for no loss.

The loudest plaudits rightly went to Victorian fast bowler Siddle, back in Test cricket for the first time in 10 months after a stress fracture to his back.

But all around the Gabba, puzzled Australians were grappling with another subject.

Could this really be the same Ian Bell who was Shane Warne's stooge on England's last, hapless Ashes tour?

He looks more or less the same, but a transformation has occurred.

Bell started 2006/07 with a half-century here, and fared better than most thereafter.

This time, though, the diffidence has gone - and surely Australia, as well as England, know he is a major player these days.

Bell's demeanour at the crease may be emboldened, but the new-found confidence has yet to follow him behind the microphone.

"It's nice to make a contribution today to get us to a half-decent score," he said modestly. "I hope I can carry on through the series now. I'm full of confidence, and we're all excited about a big series."

Bell has not quite embraced the art of self-publicity. But there is resonance, in a minor key, to his ambitions.

"I want to get stuck in through this series, and get some knocks under some real pressure.

"These are the days you enjoy playing Test cricket. Going out in front of a full house at the Gabba is pretty special."

It would have been significantly more so for England, had it not been for Siddle - whose intervention, after two earlier wickets, came with the score a healthy 197 for four.

He finished with six for 54, and Bell recalled: "We felt pretty good as a partnership, ticking along. But a great spell of bowling turned the day on its head a bit.

"We're not a million miles away from a par score. It was a slow wicket and it swung all day, which was a bit unusual.

"There are some disappointed guys, but it's (only) day one of an Ashes series.

"It was good to see Cooky get some runs, and there were periods when we played particularly well."

Bell was a powerless non-striker as Siddle took his three in three.

"I tried to pass on some info - but it probably wasn't too good by the looks of it," he said ruefully. "But the atmosphere was unbelievable, the noise and everything.

"Today was something really special to play in. Siddle bowled a great spell - two great deliveries first up to two new batsmen.

"But we're still in good spirits."

Siddle is also in high spirits, having taken his first hat-trick since he was a 13-year-old.

"It's just been an amazing day," he said, having earned his recall narrowly ahead of Doug Bollinger - another making his way back after injury.

"The crowd started to get behind me.

"It didn't really worry me too much, it being a hat-trick ball. The crowd starting roaring, and it was very loud out there and definitely did pump me up."

The toe-crunching yorker which pinned Broad lbw, upheld after a DRS process, was not exactly what he was aiming for - but Siddle was not complaining.

"I wanted to charge in, bowl fast and try to hit the top of off.

"The execution wasn't quite there, but obviously to hit him on the full like that was a dream ball that I'll remember for a long time."

Siddle, like 10 of his 11 team-mates here, still has another less welcome memory in the bank - from Australia's defeat in the final Test of summer 2009, when England reclaimed the Ashes.

His captain Ricky Ponting deliberately put the whole team through the experience of watching England celebrate at close quarters.

"I can still remember it now, the last wicket falling at The Oval Test and going out in the field for the presentation, seeing the boys going up on to that stage and 'yahooing' and cheering and getting handed the urn," said Siddle.

"It's definitely something we don't want to see again."

He could hardly have made a much better start in his bid to avoid that eventuality, but he and his fellow Australians will know already that Bell for one is a most worthy opponent.