"Our improved rating is a good step forward for a council with significant infrastructure, affordability and socio-economic challenges," he said.
He thanked the elected members and staff for investing time and effort over the last three years in an organisation-wide business improvement programme that addressed feedback in the 2017 report through 34 transformation projects.
"Our focus has been on improving our capability, systems and service delivery, as well as our capacity to deliver infrastructure projects. It is gratifying to see independent assessors recognise these improvements," he added.
Chief executive Shaun Clarke said he was proud of his staff for the result they had helped to deliver.
"The way staff have dedicated themselves to improving our business practices has been inspirational," he said.
"This report, and the feedback we have received from assessors, proves we are on the 
right track and that we will become an A-grade council if we maintain this upward trajectory.
"While we will continue to improve the customer experience across the spectrum of our activities, we also aim to be a council that listens and responds to the community and has strong relationships with strategic partners," Clarke said.