Postpublished at 15:50 British Summer Time 23 May 2015
That's a great take by Jamie Elliott on halfway from Owen Farrell's bomb. But his good work is undone as Gareth Denman knocks on and Saracens will have the put-in at a scrum on halfway.
Saracens face Bath in Premiership final on 30 May (14:30 BST)
FT: Bath 47-10 Leicester
Banahan hat-trick as Bath score seven tries
FT: Northampton 24-29 Saracens
Saracens reach fourth Premiership final in six years
Sarries tries from Strettle and George, Farrell kicks five penalties
Steve Marshall and Brendon Mitchell
That's a great take by Jamie Elliott on halfway from Owen Farrell's bomb. But his good work is undone as Gareth Denman knocks on and Saracens will have the put-in at a scrum on halfway.
That's a great kick by Kahn Fotuali'i as the replacement scrum-half plants the ball behind the Saracens defensive line and into touch in the corner, five metres from the visitors' line. You sense Northampton are cranking up the pressure with only 10 minutes to play.
We're into the final 10 minutes at Franklin's Garden then. Can Saracens hold on or is there a late twist in the tale?
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A couple of notable replacements to report. Maro Itoje's afternoon is over as the Saracens flanker is replaced by Jackson Wray, while Saints captain Dylan Hartley goes off and Mike Haywood comes on.
Ian Hunter
Ex-England and Northampton full-back on BBC Radio Northampton
"You have to take your hat off to Saracens there. Saints put them under huge amounts of pressure but they controlled their line speed coming up, and didn't rush to the ball."
Saracens' defensive work is impressive as they keep Northampton at bay but, the home side stay patient and go through the phases again, keeping the ball tight. But Sarries' resistance is rewarded when Alex Waller is pulled up for not staying on his feet and Owen Farrell clears.
Saracens are warned after Billy Vunipola concedes their 16th penalty of the game. Northampton will go for the catch and drive from the line-out again.
Saracens want to disrupt the Northampton ruck with the boot but time and again they are being pulled up for kicking the ball out of a Saints player's hands.
Stephen Myler kicks for territory, and then does so again after Sarries are penalised again for pulling down the maul, The home side are camped in the Saracens 22.
And that's three more points in the bag for Saracens as Owen Farrell makes no mistake from the 10-metre line. Sarries' lead is back up to five points.
That's a blow for Northampton. No sooner are they back in the game then Gareth Denman is penalised after losing his footing at the scrum. Owen Farrell will kick for goal.
Northampton go for the catch and drive but it all seems to be going wrong until Jamie Elliott and Kahn Fotuali'i join in to regain the momentum. It works as Tom Wood goes over and touches down, only for Stephen Myler to slice his conversion attempt wide. That's his 100% record with the boot gone for the afternoon and how costly could that be?
Credit to Northampton, though, they will not give this up. They spin the ball wide to George Pisi who is stopped in his track illegally by Owen Farrell. Stephen Myler goes for the corner.
Ian Hunter
Ex-England and Northampton full-back on BBC Radio Northampton
"Saracens are putting Saints under huge amounts of pressure and what they're doing is either turning the ball over or winning penalties. Their kicking has been very, very accurate. I'm very impressed.
"I don't think the injuries have helped Saints. They have lost a bit of momentum."
Phil Parry
Journalist, BBC London Sport
"You can feel it around the stands that there's a bit more tension from both sets of supporters. At this point, you can't afford a mistake or an error, it ends up being more costly than earlier in the game."
Saracens lead by seven points as Owen Farrell makes it four kicks from five as he lands from the tee once more.
Saracens' energy levels appear to be higher than Northampton's at the start of this half. With a stronger-looking bench is this their chance to take control. They have a penalty coming too midway inside the Saints half after Tom Stephenson is penalised for not rolling away.
Northampton's replacement bench is emptying quite rapidly as Lee Dickson heads off for a head injury assessment and is replaced at scrum-half by Samoa international Kahn Fotuali'i.
Saracens have been pretty undisciplined so far this half and Mako Vunipola is penalised on halfway for trying to kick the ball out of Lee Dickson's hands. Northampton will kick for territory once more.
George Kruis takes the ball at the back of the line-out and the Saracens pack power forward, driving hooker Jamie George over the line. Owen Farrell adds a tricky conversion from near the touchline. Northampton led for only three minutes but they're behind again now.
Once again, a penalty is followed by another penalty as Saints are penalised on their own 22. It's on the touchline so rather than go for the posts, Owen Farrell kicks for the corner. It's Saracens' turn to try their luck from a set-piece.