Harmison delivers his Ashes message
Warwickshire 264 for 9 (Harmison 5 for 39) trail Durham 433 (Blackwell 158) by 169 runs
Steve Harmison presented England's selectors with a tantalising pre-Ashes dilemma, and in the process earned Durham the chance to move to the top of the Division One table, as he belied a slow pitch to produce his second five-wicket haul in as many innings to rip the heart out of Warwickshire's batting.
In two hostile spells after tea, Harmison claimed 5 for 18 in nine overs, leaving Warwickshire's last pair requiring 20 more on the final morning if they are to avoid the follow-on. Had Boyd Rankin not been dropped off the penultimate delivery of the day, edging the deserving Graham Onions to Gareth Breese at first slip, it would have been enforced already. As it is, Warwickshire's unbeaten record that stretches back to 2007 is in severe jeopardy.
It was the manner of Harmison's wickets that was most impressive. He tore through Warwickshire's much-vaunted middle-order in an outstanding demonstration of sustained aggression, making international batsmen appear timid and uncertain.
Nor was the damage just on the scorecard. Harmison also landed three crashing blows on the head, hand and arm of Tony Frost, Ian Bell and Chris Woakes respectively. It was, one lot of five wides apart, a top-quality spell of fast bowling that will not so much nudge the England selectors as grab them by the shoulders and shake them.
"It's the worst thing in the world when you hit somebody," Harmison said afterwards. "I really don't like it at all. I **** myself when I hit Tony Frost. I was upset by that. And the same when I hurt Ian Bell.
"But on flat, slow wickets, you have to do something different and my variation is being aggressive and bowling bouncers.
"There's not been a result here in 20 championship games and you can see why. There's not much pace in the pitch, but it does have good carry. You have to have something different if you're going to win here. If we can make them follow-on we can put some nervous twitches inside the Warwickshire dressing room.
"I showed my experience today. In the last two weeks I haven't had to exert myself because of the wickets we've been playing on. I've had rewards in all three games, but this one is the most pleasing because it is a flat wicket. I had to exert myself a lot more today.
"And I came up against good players. Belly is a really good player. For him not to be in the Test team is something I struggle to comprehend. And the way Frost carried on after being hit on the head was credit to him."
Bell and Frost had added 129 for Warwickshire's second wicket. While both endured some torrid moments - Frost was struck a fearful blow on the side of the head as he ducked into a bouncer - they demonstrated courage and technique to see off the new ball. Bell, in particular, looked serene.
But doesn't he always? The criticism he has to answer is that he doesn't go on to produce match-defining scores and both he and Frost will reflect that, with the hard work seemingly done, they allowed Durham back into the game.
First Frost edged a decent ball on off stump from the medium-pace of Dale Benkenstein, before Bell was drawn into prodding at one that he could easily have left. His aghast response to his dismissal spoke volumes.
But it was the return of Harmison than prompted Warwickshire to lose six for 62. First he bowled Jonathan Trott, who played slightly across a fuller delivery that took his off stump, before unleashing two ferocious short balls for Troughton and Ambrose. The former got himself in a horrible mess and gloved a catch to slip, while Ambrose was undone by extra bounce and caught off the handle of the bat fending a brute of a ball from his face.
Woakes resisted for a while, driving Onions for three boundaries in an over. But the ball after sustaining a thumping blow to his right forearm - he was, absurdly, not wearing an arm guard - he prodded tentatively to slip. Jeetan Patel, backing away so far he was in danger of treading on the square leg umpire's toes, sliced to slip moments later.
Forcing victory may not prove easy for Durham, however. Callum Thorpe has a side strain and my be unable to bowl, while Breese was ineffective.
Earlier Ian Westwood played across a full ball and Neil Carter was beaten by one that turned sharply and struck on the back leg by the impressive Ian Blackwell. Spin could yet play the decisive role in this game.
Harmison dismissed the significance of producing his season's best performance in front of England selector Ashley Giles. "The selectors are there all the time," he said tactfully. "That doesn't bother me one bit. My agenda is to try and take 20 wickets for Durham. Everything else is out of my hands.
"Ashley knows what I can do. We've played a lot of cricket together. He's stood at gully and watched me bowl like that a few times. I like to think that, wearing his England hat, he was happy. But wearing his Warwickshire hat he's thinking 'let's get past this follow-on.'
Harmison also had warm words for his team-mate from the 2005 Ashes, Simon Jones, following his latest - and surely last - injury setback "It's horrendous," Harmison said. "Just so, so sad. I'm so disappointed for Simon.
"I remember carrying him off on a stretcher in Brisbane when he first did it [the knee injury] and it's heartbreaking to hear he keeps getting injured again. But he's a fighter and he'll get himself back on the field. Everyone's thoughts are with him."
George Dobell is chief writer of Spin magazine