We're going to have a quick check for a run out after a direct hit but the batsmen don't look too concerned.

Dave Wood: Adam Zampa is really just a very poor man's Shane Warne. Blond hair and an Australian passport is about as much as they have in common.

Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special

Zampa has bowled his fair share of loose deliveries. He's dragged down at least three or four in the last couple of overs.

Dan Norcross adds: I'm somewhat baffled as to why Zampa's still in the attack, but England aren't complaining.

Eng 252-2published at 38 overs

38 overs

Huge!

There's no stopping Jason Roy. Another ineffective leg-spinner from Adam Zampa and Roy launches the ball into the sight screen.

Roy has now equalled his highest ODI score.

More rubbish from Zampa. Down the leg side and Joe Root helps himself to four down to fine leg. We shouldn't be surprised that England's one-day team are doing this after recent performances but after the results this winter I can't help it.

Ben Thapa: Everyone saying Roy should remain a limited-overs player, that they’re different forms, remember: 1) Kevin Pietersen was promoted to Test side on the back of big ODI runs. 2) Dawid Malan was promoted to Test side, despite averaging 36 in CC, based on one T20 knock.

They're starting to mention the double century on TMS and it had just crossed my mind too. Roy would have to score a large portion of these runs if he is to get there but Joe Root does not look interested in smashing his way to the finish line. He is just knocking the ball around and making sure he is there at the end.

Could Jase do it? Maybe. One landmark definitely on the horizon is the record one-day score by an Englishman. That is currently 171 held by Alex Hales.

England add four more singles to the total as they continue to see off Pat Cummins. This is serene.

Ben Stone: I disagree with people suggesting Jason Roy couldn’t play Test cricket. Averages 37.72 in first-class cricket & has shown he can score runs vs international bowlers. We dropped Eoin Morgan after a poor series in the UAE in 2012. We don’t have the plethora of options that says runs vs international bowlers in any form of game shouldn’t be considered.

150 for Roypublished at 36 overs

36 overs

Need 70 from 14 overs

He goes on and on and on. The Aussies have their hands on their heads as a tickle down the leg side gives Jason Roy four. He then tucks two more off his hip and that takes him to 150, the second time he has passed that mark in his career.

This is already the sixth highest individual score at the MCG. The record is held by Mark Waugh on 173. If Roy stays in he'll smash that.

Robert Stow: Everyone on #bbccricket, external advocating the ODI team replacing the Test side have forgotten Hales nicking off to everything when he had a chance. Not saying the Test selections have been right but it’s a completely different format.

As Dan Norcross rightly points out on TMS, Australia desperately need a wicket but they're fast running out of front-line bowlers to get them that breakthrough. Starc has three overs left, the same number as Pat Cummins will have after this one, but there are still 15 overs left in the innings.

I think this is going to be Jason Roy's day. First he tries to hit Cummins out of the MCG but misses without edging behind and then he plays a peculiar shot, ducking to a bouncer with his bat in the air and the ball hits the edge and flies in the air before dropping safely at fine leg.

Todd Mills: Aussies just can't applaud anything English. I've now seen 'Jason Roy - close calls' montage three times!

Chris Manning: Aussie, Aussie, Aussie? Roy, Roy, Roy!

Excellent fielding on the mid-wicket boundary by Pat Cummins shows the Aussies haven't given up yet. They won't hand England a first win on this tour. Cummins prevents the four but Roy still adds three.

No stopping this one! A shocker of a delivery from Zampa and Roy hits it to mid-wicket again but this is comfortably over Cummins' head for six.

Rubbish from Zampa. Excellent from Roy. He and Root have now put on 162.

Zampa is back. His economy rate of under six per over has been good but he hasn't looked like getting a wicket.

Jason Roy is on 131. That's the highest score at the MCG in ODIs by an England player, passing David Gower's knock in 1983.

Jim Maxwell
BBC Test Match Special

The drinks are coming on. The Australians may need a gin and tonic pick-me-up, and while it wouldn't be right for England to be celebrating with the champers, it might not be too long.

Oh yes! What a shot this is from Jason Roy. Does he not know what Mitchell Starc has been doing to Englishmen this winter? Roy shows utter disdain to a back-of-a-length delivery from the left-armer and with a clean swing of the bat the ball whistles to mid-wicket for four.

That'll be drinks. I don't mean to tempt fate but how many would you have been backing England to score from here if they were batting first?

Ebony Rainford-Brent
Ex-England batter on BBC Test Match Special

Smith probably had another half-second to set himself before throwing at the stumps. Root was gone... maybe Smith is human after all.

I sense that Roy wants to make the most of it for the next seven overs before the extra fielder can go out.

Very nearly all my fault.

Joe Root foolishly goes for a single, testing the fielding of Steve Smith at backward point. The throw comes in as Root races towards the non-striker's end but the Yorkshireman would have been well short. Thankfully for Root the throw misses.

Joe Root has just been so serene in this innings. He hasn't looked troubled once. I'm not sure he's hit the ball in the air at all. Chanceless.

He is happy to accumulate but Jason Roy is still looking for the rope!

He pulls a long hop from Marsh over short fine leg for four. Onto 125 he goes.

David Guy: I'm a huge Jason Roy fan but anyone who thinks after this knock that he should be in the Test side is mad. Tests are long days, a totally different bag to this ODI and totally different cricket. Keep him as a good ODI player.