“I have no doubt about the commitment of John and his people at the political level,” he said. “[But] however, the council is struggling at officer level to keep pace.
“My experience with Councilor Cotton and his executive team is that they are determined to get this council back on its feet.”
He said they were making decisions that were “difficult” and “painful,” including whether to sell city assets.
He added that most authorities will not hold assets that provide less than an 8% return, and that they cost more to hold than they contribute financially.
Mr Caller said leaders were “still doing the very painful things” and were yet to tackle procurement savings to save services.
Speaking about a recent row over commissioners exercising their powers over a proposal to close four day care centres, he said the delay in a decision was costing around £100,000 a month.
He added that the board was able to scrutinize the proposal and that commissioners “very, very rarely” exercised their authority to block a call.
“If there was no inspection, it would be different,” he said.