Shaun Marsh pushes away the first delivery from Moeen Ali after lunch for a couple.

Moeen then strays too full, Marsh clipping off his toes to the fence through mid-wicket.

Anyway, while the no-ball debate rumbles on in the background, there is cricket to be played.

Here are the players back out on the field and here we go...

Image source, Gett

Richard Wilson: I think most agree it’s unclear. On field decision by umpire was that it was a legal delivery - surely it needs to be a clear no ball to then override that?

Image source, PA

There is a case that the bulge of Mason Crane's heel may have been behind the line. But I'm not surprised that was judged to be a no-ball. Every tight call recently seems to go that way.

Perhaps it is time that the third umpire should be watching for the no-ball every delivery and then alerting the on-field umpire if a no-ball has been bowled that might've been missed. Maybe through a watch similar to the goal/no goal system used in football?

Diccon Thornely: Based on the letter of the law, I think there is raised heel behind the line. Surely at least there should have been consultation with the on-field umpires. Like referees in rugby?!

Image source, Gett

We've just tried using a line on the carpet in the office and trainers that have different bulges in the back, relative to the sole of the shoe.

We've got no closer to an answer as to whether that was a no-ball or not.

It's 2am and it's been a long series, in our defence.

For those who were wondering, this is what Law 21 says...

For a delivery to be fair in respect of the feet, in the delivery stride:

The bowler’s front foot must land with some part of the foot, whether grounded or raised... behind the popping crease.

It's worth remembering the key moment is when the foot lands, not where it ends up. So if you land behind the line and slide on to or over it, that's not a no-ball.

A few of you asking this - England don't lose a review for that Mason Crane no-ball.

Image source, Getty Images

Andrew Samson
BBC Test Match Special statistician

Australia still have never had a third-wicket partnership of 200 at the SCG. That one between Khawaja and Smith was 188.

BBC Test Match Special

Over on Test Match Special during the lunch break, Glenn McGrath is talking about the McGrath Foundation and the work it does in breast cancer support and education.

Listen in by clicking the tab at the top of this page or over on BBC Radio 5 live sports extra.

Cheers, Amy. Great stuff.

And yes I bet there will be a lot of roughly drawn lines on still images of that 'proving' how it was or was not a no-ball.

This is going to go on in a similar fashion to when Moeen was stumped at the Gabba. Some people will see it as out, some people won't.

Right, I'm off for a break. Jack Skelton will take you through to tea.

Tom: More poor umpiring there - Crane has been close on the front foot a few times but only gets called when it’s a potential wicket by the 3rd umpire. How can he adjust for something he doesn’t know about? This needs addressing - on-field umpires need to be better.

Ed Smith
Ex-England batsman on BBC Test Match Special

We have seen a bit more turn in this pitch now to make you think the spinners will come more in to play from now on. If England can get somewhere near parity then they are on the better side of the equation. But that's looking a very long way off.

Australia still trail England by 69 runs. You'd like to think that wicket has done something for Moeen's confidence. He looked worn out when he was doing his various media jobs this morning.

Simon Mann
BBC Test Match Special commentator

It's remarkable how you can watch a morning session that seems to be going one way so completely but then a couple of incidents near the end can make you think, "Hang on."

England are still unconvinced by that no ball call, I suspect. Though a spinner, of all people, shouldn't be bowling a no ball.

Anyway, still very much Australia's session, although Moeen has denied Steve Smith what felt like another inevitable century.

And breathe...