Ian Bell pulls Glenn McGrath for four as England get off to a steady start on day four in Perth

Alastair Cook blocks another ball with England needing to bat out two days to keep their Ashes defence alive

Shane Warne looks on in disbelief as umpire Rudi Koertzen rules against an lbw appeal against Cook

Cook and Bell look comfortable at the crease and are even able to raise a smile during a drinks break

Bell raises his bat after scoring his third half century of the series, England reaching 99-1 at lunch

Whatever Bell can do, so can Cook and he is relieved to score his first 50 of the series in Perth

Warne has a number of appeals turned down by Koertzen, all correct decisions, much to his annoyance

A relieved Ricky Ponting congratulates Justin Langer after he catches Bell on 87 to make the breakthrough for Australia

A disconsolate Bell makes his way back to the pavilion with England on 170-2 on day four in Perth

Stuart Clark receives the plaudits of his team-mates after tempting Paul Collingwood to edge a delivery to Adam Gilchrist

Collingwood makes his way through a flock of seagulls as he trudges off the field having scored only five runs at the Waca

Cook raises his helmet and bat in the air after completing a magnificent century with a single off the bowling of Warne

Cook and Kevin Pietersen take a breather as they continue to add runs and help guide England to 250-3

McGrath celebrates after finally claiming the wicket of Cook with the England man edging the ball to Gilchrist

Cook hits the ground in disgust despite scoring 116 off 290 balls, as he knows England's chances are all but over

McGrath removes the off-stump of night-watchman Matthew Hoggard two balls later as England are reduced to 261-5

Pietersen and Andrew Flintoff leave the field after surviving a few scares in the final overs with England on 265-5 at stumps