Andy Warwick and Marty Moore are straight on the pitch. Tom O'Toole and Kitshoff make way.

Nathan Doak joins them in place of John Cooney.

It's not a first Ulster try for Steven Kitshoff!

Ulster did really well in the build-up and worked it wide, which allowed the Springbok prop to drop over the line in the corner.

But play was brought back for a knock on from Harry Sheridan.

Quins then win a penalty from the scrum and that was celebrated like a try!

Ian Humphreys
Former Ulster fly-half Ian Humphreys on BBC Radio Ulster

Harlequins will be pleased with how this has gone, they have the bonus point wrapped up by 50 minutes and they'll be delighted as they can't ask for much more at the start of the second half.

Ruthless, that's the big difference we have seen between the teams with whatever opportunities they've had.

Here come Ulster! Has Care's try sparked them into life?

They're deep in the Quins' 22!

Ian Humphreys
Former Ulster fly-half Ian Humphreys on BBC Radio Ulster

Danny Care you just see how ruthless he is, he sees a half gap and he's gone.

Image source, Getty Images

That try moves Harlequins up to second in Pool Two, above Bath who face Toulouse tomorrow.

Ulster, on the other hand, have it all to do.

Quins win a penalty midway through the Ulster half and Marcus Smith sends the ball into the corner.

Ian Humphreys
Former Ulster fly-half Ian Humphreys on BBC Radio Ulster

It's key that the next score is Ulster's and to get a little bit of confidence. If Harlequins get another, I imagine their confidence will be up.

Ulster are in the Quins' 22 but Danny Care pinches the ball from Tom O'Toole's pass.

The scrum-half races away and kicks downfield, but this time Baloucoune can gather while under pressure from Nick David.

Learning from their mistakes from the first half.

Tommy Seymour
Former Scotland winger on BBC Radio Ulster

In theory Ulster have come with the right game plan, and they've put Harlequins under pressure, making them defend. It's just been a little bit lackadaisical with some of the finer points.

Image source, Getty Images

James Hume has failed to return after the break and is replaced by Luke Marshall.

Fin Baxter is on for Joe Marler, too. Changes for both sides.

Nial Foster
BBC Sport Northern Ireland at The Stoop, Twickehnham.

Ulster have huffed and puffed at The Stoop in the first half but it's Harlequins who are waltzing into the dressing room at half-time bemused after being gifted 21 points.

Harlequins should be praised for capitalising so clinically on a magnitude of errors from the Ulster backline which has been met by groans of disbelief from the travelling support.

The Ulster fans, who are speckled around this famous stadium, entered The Stoop knowing that it was win or bust today. High expectations in south-west London but, like the temperature, that pre-match optimism has dropped as the first-half progressed.

Tommy Seymour
Former Scotland winger on BBC Radio Ulster

Unbelievably disappointing from an Ulster perspective.

There was a possession stat that came up with ten minutes to go in the half that showed that Ulster nearly had a 90% territory compared to Harlequins.

It just seems that Harlequins have not had to worry for their scores, and they have not had to be putting Ulster under pressure.

Ian Humphreys
Former Ulster fly-half Ian Humphreys on BBC Radio Ulster

Ulster can't afford to get behind because when they start chasing then that gives opportunities to Harlequins.

They've shown in this first half that they can create opportunities so stay patient and be more active.

No prizes for guessing who the star of the half was...

Image source, Getty Images

Image source, Inpho

When Steve Borthwick named his squad for the 2023 Six Nations - his first as England boss - he had been in charge for just four weeks.

A year later, and Borthwick's feet are firmly under the Twickenham table after 16 Test matches, a five-month World Cup campaign and a respectable third-placed finish in France.

"We know so much more about the players," Borthwick said on Wednesday as he announced his revamped squad.

With seven of the starting XV from the World Cup semi-final unavailable, some never to return, this feels like the start of a new era for England - as it is for many of their rivals.

But by Borthwick's own admission, their Six Nations form of late has not been good enough, with a 40% win record across the last three championships and 50% across the last six. The pressure is on to turn this around.

There is new leadership, there may be a new style of play and there will almost certainly be new personnel.

So what can supporters expect from Borthwick's England in the coming months?

Read more here.

As things stand Ulster's Champions Cup fate is out of their own hands....

Harlequins lead after an error-filled 40 minutes.

Image source, BBC Sport

Ian Humphreys
Former Ulster fly-half Ian Humphreys on BBC Radio Ulster

For me Ulster have dominated this first half but have been unable to get over the try-line and Harlequins have been ruthless with their couple of opportunities.