Tit-for-tat exchange between chief constable and new commissioner CHIEF Constable Colin Port and the new Avon and Somerset Police and Crime Commissioner Sue Mountstevens engaged in a tit-for-tat exchange of statements about why Mr Port is stepping down. After The Post exclusively revealed Mr Port would not be seeking to renew his contract when it expires on January 26, Ms Mountstevens -- who has the power to appoint or remove chief constables -- released a statement at 7.57am yesterday paying tribute to his eight years' service. PCC Sue Mountstevens Colin Port   She said: "Avon and Somerset's chief constable Colin Port has made great improvements for this area. He has increased detection rates and reduced crime. He will be greatly missed by staff and partners I know that he will continue to do great things and I wish him every success for the future." At 9.13am, Mr Port released his statement, which included the lines: "Yesterday I had a meeting with the Police and Crime Commissioner. She told me she intends to start the process to recruit a Chief Constable to take Avon and Somerset forward. I told her I had no intention of applying for my job. A response from Ms Mountstevens came at 9.48am: "Everyone is aware that the Chief Constable's contract expires on January 26. Because of that I would like to run a competitive process to appoint a Chief Constable for my whole term of office. It was his choice not to apply, but I