The remarkable rise of Chelsea's little-known interim boss

"In 2012, I spent a year in London observing academies at different clubs in England," Hafstad, who played 260 games for the northernmost football club in the world, told BBC Sport.

"Instantly, I could see Calum was a very good coach. He listened to the players - young boys of 11 and 12 - and really understood how to work with them."

Hafstad, now Tromso technical director, said it was easy to see McFarlane "would be a great asset".

"Even then, he had a strong knowledge of the game, but what stood out most was his man‑management," he added.

Hafstad took McFarlane to Tromso, initially as as an Under-14s coach.

"He did very well in two years with us," said Hafstad.

"He moved up to coach the under‑19s and even took first-team sessions. At the time, we were in European competitions, so it was a strong period for the club.

"We've stayed in touch. I spent a few days at Chelsea's academy in November last year, so we still have a close connection. I have no problem believing he could become a top manager in the near future."

The charity that helped make him

Image caption,

McFarlane led a 10-man Chelsea team to defeat at Fulham on 7 January

After Tromso, McFarlane spent six years until 2020 working as a coach at the Kinetic Foundation.

The south London‑based football and education charity, which supports disadvantaged boys and girls aged 11 to 19, has produced both coaches and players.

It is a huge source of pride to them that McFarlane and two other of its former coaches - Dan Hogan and co-founded Harry Hudson - are part of Chelsea's coaching staff.

But the charity has faced social media abuse from some Chelsea fans who are unhappy at the club's plight and their connections with the Blues.

"There has been some criticism and abuse, which is regrettable," said James Fotheringham, who founded the charity alongside his childhood friend Hudson, now Chelsea's Under‑21s manager.

"We are a charity that exists to keep young people in education, support their development and create opportunities. The work we do speaks for itself."

Fotheringham rejected claims that Chelsea co‑head of recruitment Joe Shields had any formal connection with Kinetic, beyond scouting players from the academy during previous roles.

Leicester's Joe Aribo, Watford's Kwadwo Baah, Queens Park Rangers' Rhys Norrington‑Davies, West Bromwich Albion's Josh Maja, and Norwich's Errol Mundle‑Smith are among the players to have come through Kinetic's academy.

McFarlane was a coach tasked with getting its boys into academies.

"Calum wanted to come home - he is from Forest Hill - and joined us in 2014 after working in Norway with Tromso," Fotheringham said.

"We ultimately couldn't retain him financially, and his six-year stay with Kinetic came to an end in 2020 when opportunities followed because the work he was doing spoke for itself."

Doing the hard yards - just like Vardy

After spells at Manchester City up to Under‑18s level and within Southampton's academy, McFarlane joined Chelsea at the start of the season to take charge of their Under‑21s.

His now-assistants Hudson and Hogan also joined Chelsea's academy at lower-age groups this summer.

There has been some criticism about their lack of formal qualifications - McFarlane does not hold a Uefa Pro or A Licence - though his full‑time professional coaching experience now spans almost 15 years.

Not having the pro licence means he can only be a caretaker manager for a maximum of 12 weeks and would need to either have the qualification - or be in the process of taking it - to become a full-time Premier League manager.

Families and agents of academy players have told BBC Sport directly how impressive McFarlane had been in his role.

Chelsea officials also were also said to be pleased with his first spell as interim head coach, including the way he showed professionalism and composure while handling media duties.

He was certainly in at the deep end in January. On New Year's Day, he was planning to visit a light show with his family - until he got a call from the sporting directors to be diverted to lead the team against Guardiola and Manchester City that week.

"There is a misconception that he and the others lack experience," said Fotheringham.

"He is a fantastic man‑manager who has coached across a number of academies, and if he had stayed at Southampton, he might have had the opportunity that Tonda Eckert received when he was promoted from the Under‑21s to first‑team manager.

"We celebrate players who come from non‑league, like Jamie Vardy, so why not coaches?

"In reality, they have spent years working in academies, grassroots football and challenging environments. They have done the hard yards."