Rooney became Manchester United’s record scorer during 13 years at Old Trafford from 2004, scoring 253 goals in 559 appearances for the Red Devils.

The former England captain was linked with a move to City after handing in a transfer request at United in 2010.

Rooney eventually patched up his differences with manager Sir Alex Ferguson and stayed at Old Trafford for another seven years.

But, less than two months after his 15-game spell as Birmingham manager came to an end, the 38-year-old admits he would be open to the idea of working on the blue side of Manchester.

“It depends (on whether I’d ever be an assistant) – if Pep Guardiola comes in and asks me to be his assistant, you’d walk there,” Rooney told the Stick to Football podcast.

“You see what (Mikel) Arteta is doing now (at Arsenal) and I strongly believe a lot of that is from learning what Guardiola was doing, and so it depends on what the situation is.

“For me, the best manager is Pep and you look at how he adapts – how they (City) are playing now is not the same as how they were playing four years ago.

“He keeps making these subtle changes and then you see everyone else trying to do the same. They also work harder than anyone else.”

City, the English, European and FIFA World Club Cup champions, are 12 points better off in the Premier League than sixth-placed United, and Rooney says it is “frustrating” watching his former team under Erik ten Hag.

He said: “There’s talent in there. But I just think there’s a mindset that needs to change.

“You watch some games and I think, ‘Really good’. But then all of a sudden it’s like a switch that’s been flicked.

“They can go from being really good to really bad. There’s a lack of consistency.”

Rooney has been linked to a possible switch to boxing, with the self-confessed fight fan confirming there have been talks to get him in the ring.

He also expressed an interest in becoming a lawyer during a recent media interview, saying he had applied to Nottingham University to study criminal law when he was at Derby.

Rooney laughed on the podcast when recalling telling lawyers what to ask during his wife Coleen’s ‘Wagatha Christie’ libel trial with Rebekah Vardy in 2022.

But Rooney insists his focus is firmly on returning to management after spells at Derby, Major League Soccer side DC United and Birmingham.

“It’s all experience – I’m only 38, I’ve had three managerial jobs but I’ve got quite a bit of experience to lean on,” said Rooney.

“If you look at the three clubs I’ve managed, going in at Derby under their circumstances in administration, DC United who were bottom of the league when I went over there, and now Birmingham, who over the past 10 years have been a mess.

“I want to focus on getting back into management. The main thing for me is to completely cut out what I’ve done as a player and almost start again as a manager.

“Of course, my playing experience will help me, but I’m right at the bottom from a managerial point of view, and I want to work my way up.

“I’m not relying on what I’ve done as a player to get me into places that I shouldn’t be.

“I want to get back into managing and I want to prove myself – whether that’s League Two, League One or Championship.”