Brendon McCullum will stay on as England's white-ball coach despite his sacking as red-ball coach. There was one moment when it fell apart - an implosion from which England never recovered. Yes, there was the Ashes planning (or lack of it), Harry Brook's tangle with a nightclub bouncer and Noosa. A while back there was the tap on James Anderson's shoulder, and just recently there was Ben Stokes' ill-fated night out.

In terms of where it all went wrong, they pale in significance next to the shambolic Saturday afternoon in Perth. And it was right there, in the palm of England's hand. One calm session would, in all likelihood, have been enough to win the first Test against Australia. Who knows what might have happened after that? England did not do calm sessions under Brendon McCullum - run towards the danger and all that. Nine wickets for 99 runs might be the most consequential batting collapse in English cricketing history, with aftershocks still being felt seven months later.

All leading to this: another stunning Sunday. English cricket used to save its best for Sundays - Anya Shrubsole in 2017, Stokes twice in 2019. Now, on two Sundays two weeks apart, Stokes has walked and McCullum has been pushed. It leaves the England Test team back where they were four years ago: without a captain and without a coach.

"Time for us all to buckle up and get ready for the ride," said director of cricket Rob Key when McCullum was appointed. At the beginning, what a ride it was. England want new coach before Pakistan - who could it be? TMS podcast: McCullum sacked as Test coach. Bucket hats, nighthawks and all the golf. Some of England's most incredible wins, achieved in breathtaking style. New Zealand at Trent Bridge, India at Edgbaston, Pakistan in Rawalpindi. For a while, England were more than a cricket team. They were a feeling, a movement, and a phenomenon.

They flickered occasionally over McCullum's next three years in charge, but nothing like that heady first year. As to why the ride careered off the rails, McCullum gave us a clue on his very first day in the job. "I don't coach technically," said McCullum at Lord's in May 2022. "I understand the techniques, but for me it's more around man-management and trying to provide the right environment for the team to go out and be the best versions of themselves."

McCullum inherited an experienced group, players who had been flattened by a run of one win in 17 and stifled by Covid restrictions: Stokes, Anderson, Joe Root, Jonny Bairstow, Stuart Broad, Chris Woakes, and Mark Wood. The New Zealander liberated them, providing a freedom they knew how to use.

When the time came to build a new England team – given the age profile, this was always likely on McCullum's watch – his style was not suited to moulding a new generation. Jamie Smith, Gus Atkinson, Shoaib Bashir – even Zak Crawley and Ollie Pope. Their Test careers under McCullum started strongly. When they needed more, he could not provide it.

McCullum admitted to over-estimating the younger players' preparedness for the hostility faced on and off the field during an Ashes tour. The outcome was a 4-1 loss so damaging that England cannot rid themselves of the stench. At the end of that series, McCullum spoke in Sydney like a man who knew his time was up. "I'm open to evolution and some nipping and tucking, but without being ultimately able to steer the ship maybe there is someone better," he said.

McCullum survived, along with Stokes and Key, albeit now with Bazball-lite: a curfew, restrictions on booze, a team chef, and a beefed-up backroom staff. For a man who made no apologies for an "informal" environment, it did not feel very McCullum.

He can point to the Stokes nightclub controversy and the captain's retirement as mitigation for the series defeat by New Zealand, yet McCullum cannot argue with a record of two wins in nine, or 19 defeats in 38. The mess could have been avoided had decisive action been taken after the Ashes. Richard Gould, chief executive of the England and Wales Cricket Board, and Richard Thompson, the chair, opted against a change that felt inevitable.

By not removing McCullum then, they have wasted four months and the three Tests against New Zealand. There are now only 10 matches before Australia defend the urn in the UK next summer. Key is fortunate to still be in post, with the opportunity to appoint the next head coach. The first phone call should be to Andy Flower, the man who masterminded England's last series win in Australia and took them to the top of the world rankings.

Once a fearsome presence in the England dressing room, he is now the most successful coach in the franchise world and has adapted his methods to accommodate the attitude of modern players. Could England lure him back, perhaps with the flexibility for Flower to still work in the Indian Premier League and in The Hundred? Gould said there is a need for a "progressive" approach. If not Flower, Jonathan Trott - the former England batter who played under Flower - would be interested. Glamorgan coach Richard Dawson is highly rated. Would Australians Justin Langer or Darren Lehmann cross the Ashes divide? Andrew Flintoff, the Lions head coach, is not thought to be under consideration.

The new Test coach will have to work alongside McCullum, who remains as white-ball coach. Splitting the coaching roles has rarely worked for England – one team usually ends up taking priority – but the schedule is so demanding that doubling the responsibility becomes too difficult for one man. The new set-up will have to work together to ensure players' time is managed, and that neither team gets the rough end of selection.

The incoming Test coach will have to be comfortable working alongside a personality as big as McCullum. Once the coach is in place, a captain can be appointed. Gould suggested that keeping a split captaincy model is a direction of travel, so where does that leave Brook? He would be the most likely candidate to replace Stokes at Test captain, yet has forged a strong working relationship with McCullum leading the white-ball teams.

Could it be that Brook and McCullum stay as a pair, and the new Test coach opts for a different skipper? Flower has history with Root, for example. Might he skip a generation and go to Jacob Bethell, a man who he worked with at Royal Challengers Bengaluru? And what about Stokes, who was so adamant there will be no going back on his retirement? There are those who believe a change in management would have revitalised the all-rounder for a last crack at the Aussies next year. Does that remain out of the question? Plenty for the new Test coach - and English cricket - to ponder.

The destruction that began in Perth in November has ended in a pile of rubble in July. Someone has a huge rebuilding job ahead of them.

The highs and lows of Bazball 'I'm done' - Stokes rules out reversing retirement.