England v South Africa, 3rd Investec Test, Lord's, 1st day August 16, 2012

Finn shows his heart in full glare

It was a tight call over who would be England's third fast bowler at Lord's. The decision to stick with Steven Finn, despite his Headingley problems, was rewarded

Moments after tea, in the 59th over of the South African innings, Steven Finn's right knee hit the stumps in his delivery stride. It was the 81st ball he had bowled. Almost before the bails hit the hallowed turf, umpire Kumar Dharmasena signaled dead ball - a trend started by Steve Davis at Headingley where the first call against Finn cost England Graeme Smith's wicket.

Apparently Davis had spoken to Finn after the South African captain complained that the habit was disturbing the batsmen. Doubtless, Smith had pre-empted this having watched Finn against West Indies and timed the complaint to maximum effect, in other words once Finn had started to bowl and was in everybody's headlights. Davis then called dead ball each time Finn's knee hit the stumps and there were plenty.

As if to balance the books of fairness, some of those calls cost Smith boundaries but were well worth it, given the damaging effect it had on Finn who appeared understandably forlorn, even humiliated. How would Smith have reacted if Davis had made the first dead ball call when the ball was whistling off the middle of the bat to the boundary, rather than flying of the edge into Andrew Strauss' hands at slip? Sliding doors.

For Finn to be playing Test cricket with this problem unresolved is close to ridiculous, especially in a three-man pace attack. Both his coaches, Angus Fraser at Middlesex and David Saker with England, have worked to overcome an unusual habit which is more than just a kink, it is a malfunction.

Remarkably, Finn was somewhere near his best in the recent one-day matches against West Indies and Australia but, as Fraser pointed out, the one-day game allows him to run the ball in at the batsman from wider on the crease. In Test cricket, Finn looks to bowl from closer to the stumps and make the ball move away from the right hander. So his knee clatters into the stumps more often.

Imagine being Steven Finn for a minute, running in to bowl with the knowledge that your natural delivery stride is the subject of an umpire's scrutiny. Imagine that you know television will analyse you until words run dry; that spectators will tut-tut and ho-hum ("he's a professional for goodness sake, our chaps don't do this on the green at Upper Bottom Yately"); and that journalists will resort to cynical reflection.

Clearly enough, his action and therefore his performance is compromised. Literally, the right knee moves sideways, towards mid-on, when the leg lands on the bowling crease. Many a bowler had brushed the stumps with his hand but none that the pundits know off have had this knee jerk. It is a herculean effort to turn up. To charge in and knock over a bunch of South Africans tells us much about the man. No quitter. Truth be told he did not bowl particularly well but he has a knack, the very best knack for a man in his profession, of taking wickets. Thus England picked him, risks and jerks galore, and the reward was a trifecta in the match that matters most.

Whether he is a better option than Graham Onions is a moot point. Unbelievably, Onions left Lord's at about 10.30am and drove two and a half hours north to Trent Bridge, to play for Durham against Nottinghamshire, where he took nine wickets and effected the tenth with a run out all within a couple of crazy hours. Onions is hamstrung by James Anderson, who is a similar build and height, and is a certain selection.

England like the variety of attack provided by Finn's height and extra bounce at a good, strong pace. This weapon accounted for Alviro Petersen and Jacques Kallis, who both gloved high bouncing balls down the leg-side. As Chris Tremlett has shown previously, six foot and eight inches is the way to go. Batsmen a) find length difficult to pick and b) become cramped in response to short balls that do not have to be especially short to threaten their throat.

Not that either Petersen or Kallis were the pick of Finn's scalps. That victim was Hashim Amla, trapped on the crease and utterly beaten by one that ripped back of the seam and down the famous Lord's slope to flatten the KwaZulu castle. Selection justified: Petersen, Amla, Kallis - all makers of monster hundreds and more in the past weeks.

Finn is a man of talent and courage. This is his time so he steps to the line with commitment absolute and unwavering. He is a rock for England to carry forth, a cricketer for all seasons in all places. But he has got to stop that knee knocking. He will feel ten foot tall when he does. Not far to go then.

Mark Nicholas, the former Hampshire captain, presents the cricket on Channel 9 in Australia and Channel 5 in the UK