A couple of loose balls in the Castres attack but Edinburgh's discipline is letting them down, and the hosts have a throw on the 5m.

The resulting maul goes down though, the whistle peeps, and Freddy Douglas pops up with the ball. The penalty goes to Edinburgh!

Former Clermont and France fly-half Cammy Lopez is on the Bayonne coaching staff nowadays and is on the pitch distributing water and a few instructions as we have a small break in play.

Cracking player he was - part of that excellent Clermont team that came runners-up in this competition several times a few years ago.

Oh dear. Christian Ambadiang has just run over the top of Edinburgh's young full-back Jack Brown, and the 20-year-old's head slammed off the turf.

That's a nasty one, it looked like a concussion. Brown is back to his feet quickly, but he's whisked off the pitch and replaced by Wes Goosen.

These handling errors are counting up already for the hosts.

Luke Northmore is the guilty party on this occasion as makes the half break on the outside but the ball slips out of his hand forward.

A frustrating opening 20 minutes for Quins and Bayonne will be fairly happy with how things stand.

A couple of big hits for Edinburgh to soak up, as Lewis Wells is hit a smidge high and second-row Callum Hunter-Hill is dumped on his back.

The stats tell me that the lock is 116kgs. Imagine lifting that up.

Ohh another chance goes begging for Quins.

They find plenty of space wide but Oscar Beard is caught in two minds whether to burst the tackle or pass to the winger outside him and he chooses the wrong option as he is brought to the ground and then knocks on.

That was a real chance and a shake of the head from the Quins coaching staff tells the story.

Chris Paterson
Former Scotland international on Premier Sports

Castres were looking for that one-on-one in the outside channel. Jack Brown does well to come across from centre field to try and make the tackle but Ambadiang has too much pace and power.

And it's a great finish with just one hand.

Important turnover for Bayonne after Cadan Murley makes a good break through the centre of the pitch.

He's isolated at the breakdown though and loses possession.

It's a good contest so far.

Lots of attacking endeavour from Harlequins but the passes aren't quite going to hand at present - early days I'm sure they'll start sticking soon.

But Bayonne have given away three penalties in a row now, giving Quins possession and territory with each infringement.

Image source, Getty Images

Held up!

Edinburgh have the scrum on the five and Ben Vellacott picks up at the back and feeds to Piers O'Conor, but the inside centre is wrapped up after crashing over the whitewash. Castres can clear their lines.

A mixed start in the south of France for Edinburgh, a lot of high kicks in the low winter sun.

Lewis Wills tried to take a quick throw which has the visitors deep in Castres' half, but there's no score yet. A pause in play now as Boan Venter receives treatment.

Marcus Smith gets his hands on the ball but the move comes to a premature end with a knock-on in midfield.

The sun has just gone behind the clouds a little but it looks a great day for rugby at The Stoop.

Let's hope these two chuck the ball around a bit this afternoon to keep us entertained.

A couple of nervy moments for Castres wing Jonah Thompson who spills a kick out into touch - the sun was in his eyes in fairness - but Quins might look to target him after that start.

Quins have started well and are pinning Bayonne back.

We're under way at the Twickenham Stoop and at the Stade Pierre Fabre to kick-off another exciting day of European Champions Cup rugby.

You can listen to BBC radio commentaries of a selection of today's Champions Cup and Challenge Cup matches on this page.

Click on the "Watch and listen" tab for the full list of available options.

Edinburgh head coach Sean Everitt speaking to Premier Sports:

"We've had good prep and a lot of energy with new guys coming in. We've rested five players this weekend, with injuries in some positions. But it's a great opportunity for guys who have played in the URC to play some Champions Cup.

"If [the half-backs] do as well as they did last week, we'd be very happy. They're growing. Cammy is young, only a fourth start today, but he was really good last week. With the experience of Piers O'Conor and Ben Vellacott around him, I'd expect the same.

"It's great Matt [Currie] is back, he brings leadership and runs our defence. It's been a tough six months for him, trying to find the diagnosis [of vertigo]. There was no time span on when he was to come back, it was day to day, waiting to get better. He's been feeling good for two weeks now, so he's excited."

Tom English
BBC Scotland chief sports writer on Sportsound

After last night’s brilliance at Scotstoun, if an experimental Edinburgh win at Castres today then I might say something that I will soon regret about Scotland and the Six Nations.