Ex-Birmingham City star Michael Johnson says Steve Cotterill needs time to turn the club round and that it could take ‘a year to 18 months’ to complete the process.

The former defender will return to St Andrew’s on Saturday as Blues meet another of his old clubs Derby County, in a fixture that pits second top of the Championship against second bottom.

And having seen Blues spend a year in decline following the departure of Gary Rowett, who will be in the Rams dugout this weekend, he says one key ingredient is needed at the club.

“It is about stability now because there have been too many changes,” Johnson said.

“If you are not careful you have four sets of players on different wages, used to playing four different styles and that can only lead to a toxic atmosphere in the changing room.

“Steve has got a big job on his hands and I feel for some of the guys [off the pitch] who have been there for so many years and done a tremendous job in difficult times.

“From what I am hearing Steve is starting to sort it out and whatever happens they have to stick by Steve because changing means bringing in another person with another set of ideas and whatever they want to bring in.

“It might take a year or 18 months to turn round but it’s a process that needs to be gone through.”

The signs of a turnaround could just be evident with Blues having won their last three matches and reined in some of their relegation rivals.

Certainly their performances appear to have stabilised with three successive clean sheets and Sam Gallagher starting to find the net on a regular basis.

There are no such worries at Derby where their form is excellent and Johnson recognises the methods that brought Rowett success at St Andrew’s.

“The table does not lie. Derby are second at the halfway stage on merit - because there have only been two defeats in 19 games - but we all know it’s only January and a lot can happen between now and the end of the season,” he continued.

“They’ve been in this position before and it hasn’t worked, they’ve got to use this as an opportunity to make sure wherever they fell short in previous years, they don’t again.

“Gary has improved the backbone of the team and that’s something you knew he would do from his Birmingham days.

“I saw that working with him as an ambassador for Blues that one of his strengths is affecting people and getting them to want to play for him. He’s a good people’s person and that’s having a good effect on Derby.”