"Although there was a risk of conflict between his interests and those of his clients, he failed to advise them to obtain independent legal advice," the tribunal said.
"It was later accepted that this was a significant breach in his fiduciary relationship to his clients."
The tribunal found Mr Dallison "no longer a fit and proper person to be a barrister and solicitor".
"As regulator of the legal profession, the Law Society is committed to ensuring high standards of conduct by practitioners," Law Society president Jonathan Temm said.
"The public at large can be sure that members of the legal profession will be held to those high standards."