Kevin Pietersen is watching Jordan Cox practise his driving during the recent white-ball series against Sri Lanka, and latches on to an error with the kind of perfectionism that helped make him one of the most dangerous batsmen in the world.‘You should be annoyed you hit that back to the bowler,’ Pietersen tells him. ‘Such an easy run. That is the easiest single down the ground. That’s the level of intensity you need in the nets.’Cox accepts the criticism, and explains he was nervous of being bowled through the gate. For Pietersen – scorer of 32 international hundreds, often in breathtaking fashion – the self-doubt barely computes. ‘Don’t worry about it,’ he says. ‘You’re a good player.’The vignette is typical of his involvement with England’s white-ball set-up ever since Brendon McCullum invited him on board as a mentor last month, with a view to preparing the team for the 50-over World Cup in southern Africa in a year’s time.Pietersen speaks only when he thinks it is necessary – a departure, some might argue, from his playing career – and is unafraid to challenge. Cox, rarely short of self-belief himself, looks almost awestruck to be receiving a private tutorial from a cricketer he grew up idolising.‘He’s one of the best, if not the best, for talking to the players about batting and how to construct an innings,’ Rob Key, the ECB’s managing director of men’s cricket, tells Daily Mail Sport. Kevin Pietersen spent ‘two wonderful weeks’ working with the England white-ball teams at the back end of the summer Pietersen with England white-ball captain Harry Brook (centre) and new Test coach Stephen Fleming. ‘I will never try to take the flair and genius out of Harry,’ Pietersen says‘Hundreds are big things in 50-over cricket, and he was a run-scorer. He was one of the best at working out what the opposition were trying to do with him, then finding a way to score. Plus, he’s forthright, and both Baz and I enjoy that.’Eyebrows were raised when it emerged that McCullum had contacted Pietersen, who had been openly critical of the white-ball teams’ attitude to training during a tour of India in early 2025. Pietersen was surprised too. When he saw McCullum’s mobile number flash up, an old reflex kicked in: ‘What have I done wrong now?’But McCullum was less interested in his history of falling out with colleagues than he was in using his razor-sharp cricket brain to transform the fortunes of England’s one-day team – in the doldrums ever since lifting the 2019 World Cup, but this year hinting at a recovery.And England have been impressed. ‘I was expecting someone a lot more self-centred, but he’s in listening mode,’ says one insider, echoing Pietersen’s own claim that ‘I’m still in the two-ears-one-mouth phase’.So keen was Pietersen to resume relations with a dressing room he left amid tension and name-calling after the 2013-14 Ashes whitewash that he even brought forward his involvement: the ECB hadn’t expected him to be available until next month’s white-ball trip to Australia, but Pietersen juggled his busy calendar – including his YouTube channel, The Switch, which has over 750,000 subscribers – to ensure he could chip in against Sri Lanka.‘He’s not doing it for the money,’ says Key. ‘He could earn a lot more than the daily rate we’re paying him. The thing is, he absolutely loves it. There are technical coaches, and coaches who have done it themselves on the pitch, and he’s both.’The mantra Pietersen has been using behind the scenes is simple: ‘Train hard, play easy.’ Armed with a punishing work ethic, he expects nothing less of his charges, and he has been full of ideas, regularly leaving voicenotes for McCullum, and recently suggesting a 15-minute spin masterclass for all the batsmen, which the ECB turned into social-media content.In it, he harked back to an exercise he had practised on a tour of India with Jonny Bairstow and Joe Root, in which the players pair off and bowl off-breaks to each other. The task is to hit everything through the off side, no matter where the ball pitches, with a view to improving judgment of length. ‘He’s not doing it for the money,’ says England boss Rob Key. ‘He could earn a lot more than the daily rate we’re paying him. The thing is, he absolutely loves it’ And he has been smart enough to tailor his advice. When he told Ben Duckett to work on his game against left-arm spin, Duckett suggested the reverse-sweep. But Pietersen instantly outlawed the shot, telling him to hit straight.With Tom Banton, who scored his first hundred for England during Sunday’s series-clinching win against Sri Lanka at the Oval, he has worked on attitude.‘When you’re up, you’re not sky-high, when you’re down, you’re not down in the dumps,’ he told Nasser Hussain on Sky Sports. ‘It’s about being a constant person in the dressing room. I’ve spent time with Bantz: consistency is the theme.’Then there’s Harry Brook, who – like Pietersen before him – is praised for his talent as often as he is pilloried for his methods of dismissal, and no matter that Brook is probably the world’s best all-format batsman. Being held to a higher standard than his team-mates is a compliment bordering on a curse that Pietersen understands only too well.‘With those brainfade moments, it’s because sometimes you see the game differently,’ he said. ‘The fans have to understand that. There are times when Harry Brook stands at the wicket and says: “This is too easy.”‘I will never criticise him for doing something he thinks isn’t too much of a risk. One thing I’m working really hard with him on is situations, but I will never try to take the flair and genius out of him.’Pietersen has had his eyes opened by the rigour of England’s white-ball set-up, having previously believed it was more interested in golf and chilling. As one source puts it: ‘KP made assumptions. Now he’s on the inside loving the debate and fizzing with ideas, almost Tiggerish. He and Baz have a good relationship, but KP is clear about who’s the boss. He’s not treading on anyone’s toes, and he loves being part of a team again.’Those who followed his 104-Test electric career, the ups as well as the downs, may be holding their breath, and he remains a strong personality. ‘The best thing about this,’ he told a BBC interviewer with half a smile, ‘is I have no responsibility listening to and reading your rubbish.’ ‘He and Baz have a good relationship, but KP is clear about who’s the boss,’ says a source Pietersen will help out during the tour of Australia in November and the one-day series in South Africa in January, before reconnecting with the team next summer ahead of the World CupAfter his initial fortnight with England – ‘two wonderful weeks’, he calls it – he will not go to Pakistan for this month’s ODI series but will help out during the tour of Australia in November and the one-day series in South Africa in January, before reconnecting with the team next summer ahead of the World Cup.Inevitably, he has been asked whether he might extend his mentorship to the Test side, but he has played down that possibility, citing the extra scrutiny – ‘that’s not the world I want to live in’ – and his commitments away from the game.And yet, by the time the Ashes come round next summer, only Root will have had any experience of beating Australia. Pietersen, on the other hand, tasted series wins against the Aussies four times. We may yet be in for another surprise.