"Chris Gayle's the big wicket you want to take. If you want to be a T20 specialist around the world you've got to play against and take the wickets of the best players."

Tymal Mills is not shy declaring his ambitions before Sussex meet Somerset on Wednesday night in Hove. It is not only Gayle's wicket Mills is after: he also seeks reaffirmation that he is the fastest bowler in England.

"Yeah, probably," he proclaims breezily. "We're playing on TV so I'll have one eye on the speed cameras probably, to see how I fare. I've not bowled on TV since last summer."

Though he is not yet 24, there has long been a sense of showmanship to Mills. In a cricketing culture famed for conservatism, the old rules - that reputation is garnered solely through hard-won results in the shires - have been thrown out for Mills, who has induced excitement far out of proportion to his still underwhelming statistics.

But the point isn't these numbers; it is 90mph, a figure Mills has regularly vaulted over in front of the cameras. He reached 94mph for Essex versus an England XI three years ago, imperilling Graeme Swann's Ashes involvement after hitting him on the arm.

"I'm not camera-shy, and like to think I do step up to the moment and enjoy it," Mills says. "The boys wind me up about it, saying I bowl 5mph quicker on TV."

Besides rattling Gayle and ratcheting up the speed gun, Mills has another aim. "I've got to get my face out there if I'm going to forge a good career playing T20s around the world. In the group stages we play two, maybe three, televised games so I've got to make sure I bowl well in those games."

Mills has attributes to make him coveted in T20 leagues the world over: he is a quick left-armer with a potent yorker and bouncer, and a penchant for pressure moments. "I like to bowl at the death and in the Powerplay - they're obviously the two hardest times to bowl, so if you can get a reputation for being good at bowling at both times you're going to make yourself a more valuable commodity in T20."

"I'm not camera-shy, and think I do step up to the moment and enjoy it. The boys wind me up about it, saying I bowl 5mph quicker on TV"

He expects to be bowling up the hill to Gayle, "because it's the harder job to do".

For all his brawn, Mills has the brains to thrive in the format too. "I'm lucky the way I bowl my slower ball, it's quite hard to pick. When I get it right, my slower ball is my best ball - I get good bounce on it and can bowl it at different lengths."

His variety of slower balls could be enhanced by working with Bangladesh's Mustafizur Rahman, who will shortly join Mills to play T20 cricket at Hove. "He's got rubber wrists," Mills says. "That's how he can bowl all his cutters." It could be quite a sight: the fastest bowler in England at one end, the most cunning T20 bowler in the world at the other, and Chris Jordan in support.

****

Unlike so many other T20 specialists, Mills' path came not out of choice but was forced upon him.

On May 14 last year, he strode into an office in Hove, where he was greeted by Sussex's chief executive, coach and several doctors. They told him that he had been diagnosed with a rare congenital back condition that could cause substantial mobility problems if he continued to bowl in first-class cricket. At the age of 22, Mills had to retire from the first-class game: the Test ambitions that had sustained him since he was a boy, and which he had just moved to Hove to pursue, were destroyed.

"I went home and was thinking, 'Oh God, what am I going to do here?'" But amid the disappointment there was also profound relief. In the weeks after Mills' involvement against Worcestershire was curtailed by back pain, he had been tested for a range of far more serious illnesses, including multiple sclerosis. Those tests had come back negative.

"Nothing like this had happened before in cricket so they shared it with different doctors and got opinions from guys in America, seeing if there was anything in baseball that was similar. They came to the conclusion that the ramifications down the line could be not great. It's your back, it's pretty sensitive, so you've got to take the safe option. It's just the way I'm put together, really. It is what it is, but you've just got to accept it and get on with it."

Three days after being told the news, Mills was selected to play Gloucestershire in a T20 Blast match. "The first ball, I was a little apprehensive. I wasn't worried about how the cricket would go, it was more about how my body would go."

His body held up, and so did his bowling. Mills took 3 for 30 against Gloucestershire, his career-best figures at that point. By the season's end he had taken 19 T20 wickets at 18.84 apiece. It was enough to keep him firmly in England's minds.

Two years earlier Mills had been touted as England's Mitchell Johnson during the 2013-14 Ashes, despite a record of record of six Championship wickets at 66.33 in the 2013 season. He can laugh about these surreal weeks, which included giving a huge bruise to Alastair Cook in the nets. Now Mills has the chance to build a more substantial relationship with England.

Tymal Mills produced a short but successful spell with three wickets Action Photographics

Their interest is palpable. Last winter he was selected in the England Lions squad for a T20 series against Pakistan A, between trips to South Africa.

Mills also has a personalised training programme devised last October by Pete Atkinson, England's lead strength and conditioning coach. "He became my personal trainer over the winter - we couldn't get away from each other."

The regime for Mills is very different to most cricketers. That it does not include any weights is not just because of his back but his build as well: more middleweight boxer than archetypal fast bowler. "I'm a bit different to most guys, because I'm not really built like a cricketer. I'm bigger than most people."

While Mills' new ambitions feel altogether more realistic than the hope that he could replicate Johnson in whites, there remain significant obstacles.

The first is the schedule. In an age when complaints about the onerous, ever-shifting county fixture list seem ubiquitous, Mills faces an altogether different problem: not playing enough. June has begun, and he has only bowled two overs all season, in a rain-affected T20 in Bristol.

"This last six weeks has been a bit tough, just training. It's been a long pre-season, watching the boys play. It's been a means to an end, but it's a necessary evil."

When his T20 season starts in earnest, Mills will still be restricted in his training regime. Last year his schedule was reminiscent of Ledley King's during his final years at Tottenham Hotspur: King would not train at all between weekly games.

Mills is now able to spend time in the nets - his back doesn't give him "any day-to-day problems" - but at England's behest, he is still carefully managed. In an average week he expects to play in a T20 game and then bowl a couple of five-over spells in the nets, although that might be upped when the 50-over county competition begins.

If there remains a pang of regret at being denied the chance to try and pursue a Test career, Mills is a man "at peace with it". He knows, too, that he has been lucky in his timing. Had he been born a decade or so earlier his back condition would have ended his professional cricket career.

Now, misfortune has afforded Mills the opportunity to be a trailblazer. In an age when English attitudes to T20 are warming, thanks to a vibrant World T20 performance and Andrew Strauss' enlightened approach, Mills can mark himself out as England's first true specialist T20 bowler, a bowling equivalent to what some radicals hope will become of Jos Buttler. "In a perfect world I could make a career doing this for a long time. I've just got to stay fit."

Mills hopes that fully committing to mastering the subtleties of T20 bowling, rather than simultaneously trying to find his way in the first-class game too, could "give me the edge".

When not hurtling the ball down at speeds seldom spotted in the county game, he is not a man prone to looking back. He has not even picked up a red ball since last summer. "Everything I do is aimed at being a top T20 player. I want to play for England even if it's just in T20 cricket."