Spreckley founder Mike Spreckley is relinquishing his MD role at the 20-strong consultancy to Butters, but will carry on as chairman.
Spreckley said: 'He will take over the challenge of developing the clients and staff and I will continue to look after some clients and have responsibility for the financial side.'
Butters joins a management team that also includes director Richard Merrin and associate director Chris Skyrme, who joined in December from Cohn & Wolfe's corporate division, where he was an account director.
SP clients include Henkel Consumer Adhesives, Pitman Training and Business Post.
Butters leaves B-M this week after seven months in the role. It is understood B-M is now looking to replace him.
He previously spent eight years at tech shop Harvard PR.