Threesixty is a compliance consultancy firm and was bought by Standard Life in March 2010.
Mr Chamberlain said it had "proven impossible" for Threesixty to demonstrate its independence since being acquired by Standard Life.
He said: "Since its acquisition by Standard Life, it has proven impossible for Threesixty to demonstrate its independence in the market place.
"As compliance holds such an important place in the continued growth of our 45 member firms, Succession has taken the view that this conflict of interest can no longer be tolerated."

Mr Chamberlain said all other firms that Succession worked with understood the business objectives of the firm.
He said: "Succession works with a large number of preferred partners to deliver a wide range of professional and support services to meet the complex needs of our profitable wealth management firms who are transitioned and ready for the RDR.
"We have confidence that all of those partners understand and support the objectives of our business."
Succession has 45 member firms but only seven use Threesixty's services.
Phil Young, managing director of Threesixty, said: "Our primary purpose is to protect and advise the clients we look after. This doesn't always suit everyone, and we believe this statement was an occasion where that has happened.
"The reaction of our clients has been both humbling and encouraging and we think it speaks volumes for our reputation in the market. We have a good relationship with advisers, platforms, providers and fund managers throughout the industry and I haven't seen any evidence of dissatisfaction from anyone else."