McCullum’s contract with England ends in the autumn of 2027. He said he has not thought about the possibility of an extension so, as it stands, his final Test series in charge will be the home Ashes next summer.
By then, England will have not held the urn for almost a decade and not won a five-match series since 2018.
And 44-year-old McCullum, who played 101 Tests for New Zealand, said his team must use their latest Ashes failure as a “lesson” for the challenges ahead.
“The lesson we were taught down in Australia needs to help galvanise us moving forward, otherwise it was just a beating and incredible disappointment,” he said.
“If we’re able to make good on what we’ve been taught and what we’ve gone through and it makes us a better side, whilst it still hurts, it will make us a better side.”
In the aftermath of the Ashes, players who have been discarded by McCullum’s regime have been critical of the England set-up. Liam Livingstone and Jonny Bairstow added their voices to the frustration expressed by pundits and fans.
In response to some of the Ashes shortcomings, England have added extra coaches to their backroom staff, imposed a midnight curfew on players and staff, and will soon be joined by a full-time chef.
“I’ve always had authenticity to how I like to operate as a person. It’s not going to be everyone’s cup of tea,” said McCullum. “Not everyone is going to love you all the time. That’s OK.
“I have firm conviction in the way we try to shape and build teams. I’m not rigid about development, improvement and refinement.
“There has been a period of reflection, things we have needed to change and things we have changed. We’ve made some adjustments and now the key from a cricket point of view is winning those moments when the game is on the line.”