FT: Harlequins 50-21 Northampton
Quins run in seven tries against Saints
FT: Saracens 46-31 Worcester
Sarries move back to second with win
FT: Gloucester 20-16 Sale
FT: London Irish 15-20 Newcastle Falcons
Harlequins 50-14 Northampton
Quins have scored some tries from flowing moves today, but this one is much scrappier.
From the five-metre scrum, Jono Kitto is downed a metre from the line.
Number eight Mat Luamanu pucks up and forces his way over from close range.
Teenage fly-half Marcus Smith adds the conversion and brings up the half century of points.
Harlequins 43-14 Northampton
Northampton drag down a five-metre scrum and get a penalty.
The hosts are dominant again and opt for another set piece.
Harlequins 43-14 Northampton
Almost another try for Quins, as Charlie Walker breaks through the lines and shows good pace to avoid a couple of tackles.
Just as he is looking for support, Saints flanker Jamie Gibson manages to intercept and dab down the loose ball behind his own try line.
Harlequins 43-14 Northampton
Danny Care, with two tries to his name, is replaced by Jono Kitto at scrum half.
Joe Marler has also been replaced.
Harlequins 43-14 Northampton
Quins captain Dave Ward wrestles the ball away from Api Ratuniyarawa on halfway and sets up another attack for the hosts.
The hooker has been an influential figure today, with his committed performance epitomising his side's display,
Harlequins 43-14 Northampton
Will that try, Harlequins' sixth of the game, stop the Saints comeback?
Quins are back up to 15 men now, and Northampton captain Dylan Hartley has been replaced by Mikey Haywood.
Harlequins 43-14 Northampton
Image source, Getty ImagesQuins manage to switch the momentum back their way after a strange passage of play.
A good line break from Jamie Roberts allows Marcus Smith to chip forward.
Ben Foden fumbles and gathers it, buut the Quins forwards harry him and get possession back again.
The ball is fired out to Mat Luamanu, who gathers with one hand and finds Dave Ward, who offloads smartly to Danny Care and allows the England international to finish from close range.
Harlequins 36-14 Northampton
Harry Mallinder looks to set up another attack for Northampton, but Ben Foden's foot is just in touch as he goes over halfway.
Harlequins 36-14 Northampton
Northampton are looking much more purposeful since the break and have their second try.
The forwards drive the ball up to a metre of the line, and Nic Groom dummies a pass and dives over the line.
Saints have taken advantage and made the scoreline more respectable while Quins have a man in the bin, but James Chisholm will return in a couple of minutes.
Harlequins 36-7 Northampton
Quins make the mess of an attacking scrum for the first time.
They go for the blindside looking to get Charlie Walker in behind the Saints defence on the right, but Danny Care's kick goes out on the full.
A glimmer of hope for the visitors.
Harlequins 36-7 Northampton
And Saints have a try!
The deserve that for the pressure they have put on Quins in the last few minutes.
Api Ratuniyarawa drops the ball with the try line gaping but JP Doyle is happy that it went backwards and Rob Horne picks up the pieces to cross.
Is that a way back into the game for the visitors, who are up against 14 men?
Harlequins 36-0 Northampton
Northampton are threatening the Quins line and some desperate tackling keeps the visitors at bay.
But, as they look to go out wide, James Chisholm is offside looking to intercept the ball and referee JP Doyle does not hesitate ion sending the flanker to the sin-bin.
So, Saints have a man advantage for the next 10 minutes.
Harlequins 36-0 Northampton
Saints get another penalty after Quins collapse a mall.
Stephen Myler goes for touch again.
Harlequins 36-0 Northampton
Northampton get a penalty inside the Quins half after Mat Luamanu was ahead of the kicker from a boot forward.
Saints go to the corner in search of a try.
Harlequins 36-0 Northampton
Quins have their sixth try of the afternoon.
Marcus Smith sets it up again, with a brilliant long, looping pass out to the left to Tim Visser, who is in acres of space and dives over the line in the corner for his second of the game.
Smith narrowly misses the conversion from out wide on the left - the first error he has made today.
Harlequins 31-0 Northampton
Quins look like they will pick up where they left off, as Mike Brown gathers a high kick and carves through the Saints defence.
He kicks a low grubber towards the left looking for Jamie Roberts, but Jamie Gibson does well to cover and snaffle the loose ball about six metres out.
Harlequins 31-0 Northampton
We are back under way at Twickenham, with Quins fly-half Marcus Smith getting the second half started.
Saints have lost their last six Premiership games and look on course for a seventh, barring a mammoth comeback after a one-sided first period.
FT: London Irish 15-20 Newcastle
Adam Williams
BBC Sport at Madejski Stadium
Another defeat for London Irish and another case of “so nearly” for Nick Kennedy’s side as a tight final quarter went against them.
That’s 11 defeats in a row for the Exiles now and the deficit to Worcester remains at 10 points.
The players, coaches and supporters will hope 2018 brings a change in fortunes.
HT: Harlequins 31-0 Northampton
If you've just joined us, everything has gone right for Quins so far this afternoon.
Tries from Dave Ward, Charlie Walker, Tim Visser and Danny Care secured a bonus point just after the half-hour mark and Marcus Smith has kicked 11 points as well.
Northampton have had a torrid afternoon, and have lost winger Ahsee Tuala and Piers Francis to injury.
Will Harlequins keep their foot on the accelerator in the second half or can Saints mount a comeback?
HT: Harlequins 31-0 Northampton
Josh Verrills: Northampton seem to be getting worse by the game. Could reach the 40/50 point mark against Harlequins if they carry on as they have been in the first quarter of the game. Harlequins tearing them apart every attack
Ian: Northampton are pathetic. No Saints player deserves to be anywhere near the England squad