Willingness to defy traditional conservatism key to England's revival in Test cricket
As New Zealand captain, McCullum provided the template for England's resurgence in 50-over cricket that culminated in their 2019 World Cup final win.
The completion of England's 3-0 series success over Pakistan on Tuesday was the latest chapter in a remarkable revival, all the more extraordinary for the woeful run of red-ball results that preceded the 'Bazball' era.
Inflicting the first home whitewash suffered by Pakistan in Test history, courtesy of an eight-wicket win in Karachi on Tuesday, was striking enough in itself.
It also gave England their ninth win in 10 matches at this level, with Test world champions New Zealand, India and South Africa also among the vanquished, since captain Ben Stokes and coach Brendon McCullum took charge in May.
When they joined forces, however, England had won just one of their 17 previous Tests.
So how to explain the stunning turnaround?
The answer begins in April, when the England and Wales Cricket Board (ECB) appointed Rob Key, a former England batsman with a modest Test record, as their new director of cricket.
The 43-year-old, previously a television pundit, has since seen his judgement vindicated repeatedly.
As New Zealand captain, McCullum provided the template for England's resurgence in 50-over cricket that culminated in their 2019 World Cup final win.
Key backed him to have a similar impact on the Test side when he named him as a permanent replacement as coach for Chris Silverwood was sacked after England's 4-0 thrashing in Australia.
Star all-rounder Stokes, 31, not long back from a mental health break, replaced close friend Joe Root as England captain, with the outstanding batsman drained by leading a losing side playing under severe Covid restrictions.
Numerous observers noted how the form of England all-rounders Ian Botham and Andrew Flintoff had slumped during their unsuccessful spells as Test captain.
Nevertheless Key, preferring his opinion to the weight of history, said: "I believe in Brendon and Ben Stokes... Time for us all to buckle up and get ready for the ride."
And what a ride to date, with Stokes and McCullum capitalising on the feel-good mood created by the end of 'bubble' life.
In the new environment players are encouraged to enjoy cricket and not fear failure.
England's attacking approach, dubbed 'Bazball' in honour of McCullum's nickname, although he dislikes the term, has been based on aggressive run-scoring that allows bowlers the time to take the 20 wickets needed to win a Test.
McCullum has realised advances in limited overs run-scoring -- on show in England's recent T20 World Cup win under white-ball coach Matthew Mott -- can be applied to Test cricket.
That expanded range of strokeplay, allied to classical shot-making, saw England become the first team to score 500 runs on the first day of a Test when Zak Crawley, rising stars Harry Brook and Ollie Pope, as well as Ben Duckett, all made hundreds in the Pakistan series opener in Rawalpindi.
England's new attitude is also evident in Stokes' willingness to risk losing a match in pursuit of a win.
In Rawalpindi, Stokes' bold declaration, that left Pakistan needing 343 to win in four sessions, was rewarded with victory shortly before bad light threatened to end the match.
England's willingness to defy their traditional conservatism was equally visible when 18-year-old leg-spinner Rehan Ahmed became the youngest Test debutant from any country to take five wickets in an innings during the Karachi finale.
Stokes has also proved himself an astute man-manager, reinvigorating veteran quicks James Anderson and Stuart Broad, while giving a much-needed confidence boost to left-arm spinner Jack Leach.
Have England changed Test cricket? Perhaps not but former captain Michael Atherton, noting how the current England team's approach had faced scepticism at every turn, wrote in The Times on Tuesday that Stokes' men had won in Pakistan by "playing with more verve and attacking intent than any England team, surely, has ever done".
For some the acid test remains next year's Ashes series at home to arch-rivals Australia.
Stokes acknowledges that winning makes it easier for England to "enjoy" themselves and is doing his best to head off the doubters.
"The real test will be when things don't go so well," he said. "And that will be the time to make that (enjoyment) even more of a thing for us to take out there. But I hope we don't come to that."