Watch Buttler's half-centurypublished at 18:06 British Summer Time 26 May 2018
Here's the half-century that spared England's blushes...
England fight back in final session
Buttler (66) & Bess (55) put on 125
Bess makes fifty on Test debut
England lost four wickets in 37 balls
Captain Root lbw to Abbas for 68
First Test of two-match series
Amy Lofthouse
Here's the half-century that spared England's blushes...
Lead by 40
Whoops. Jos Buttler almost does himself a mischief and get stumped down the leg side in the process as he attempts a sweep to Shadab Khan.
More runs there, though, as Buttler whips for one, before Dom Bess ensures he keeps the strike for the next over.
Waqar Younis
Former Pakistan pace bowler
The pitch is at its best. The first two days there was hardly any sun so it is fresh, it has been a very good batting pitch.
It does look very easy for England in the evening light, as Dom Bess and Jos Buttler work Mohammad Abbas for some easy singles.
Andrew Samson
BBC Test Match Special statistician
The hundred partnership from 170 balls and 13 fours. Pakistan conceded a hundred partnership for the seventh wicket in the second innings against Ireland also, 114 on that occasion.
Just a couple from Shadab Khan's latest over.
There's 12 overs left in the day at Lord's.
#bbccricket
Ben Thapa: Really important England try and make hay in these late overs against a tiring attack. It will be hard to start again tomorrow.
pete: Nice quick double century from Buttler and this match will be a doddle!
Lead by 33
I have no idea if Jos Buttler intended to play a little dab, or if he was trying to leave the ball and it took the bottom of the bat, but whatever the case, it's run away for another couple of runs.
Simon Mann
BBC Test Match Special commentator
For the first time in the game almost this Lord's crowd comes to life, England at last giving them something to cheer.
Eng 210-6
Shot! Oh, that's gorgeous from Dom Bess, standing tall and rocking back to drive Mohammad Abbas for four.
A single brings Jos Buttler on strike, and then a leggy delivery from Abbas beats everyone, racing away for four byes.
That'll be the 100 partnership up, too. A terrific performance from Bess and Buttler to stop England subsiding.
Mohammad Abbas is back on for a brief blast.
This partnership is now worth 91 runs, incidentally.
Waqar Younis
Former Pakistan pace bowler
Young Bess has played really well, I have enjoyed the batting from the young players on both sides, with Shadab for Pakistan. Bess has managed the spin, I was thinking he might struggle against Shadab.
Lead by 22
The shadows are starting to creep onto the pitch as a thudding Jos Buttler drive brings up England's 200.
Leggie Shadab Khan readjusts, and then ends up wincing in pain as his teammate throws the ball back to him and cracks him right on the index finger. Ouch.
Lead by 20
Heart in mouth moment for Jos Buttler, as he goes hooking and just about avoids sending Hasan Ali's latest delivery into the waiting fielder's hands.
Andrew Samson
BBC Test Match Special statistician
This is Jos Buttler's second first-class fifty in three years.
Lead by 18
A full-blooded thwack goes flying towards the fielder at mid-wicket, who pulls off a fine, diving stop to keep Jos Buttler on strike.
Waqar Younis
Former Pakistan pace bowler
Buttler has learned from his mistake in the first innings and he is looking very good.
Eng 196-6
Four - and that's a half-century for Jos Buttler!
Grins all round, particularly from Joe Root in the dressing room, as Buttler raises his bat to an appreciative Lord's crowd.
Lead by 13
Dom Bess drops the ball into the off side and calls Jos Buttler through for a quick single. Smart running.
Hasan Ali, who hasn't quite got it right in this spell, goes short once again, and Buttler rolls his wrists for an oh-so-easy single.