Roberts, who has been acting as a consultant for the accountancy firm since he left the staff in April 2001, joined Tamesis this week.
With a 15-year track record at KPMG, he has recently been giving advice on its anti-money laundering project for the state of Liechtenstein.
Joining Tamesis as senior consultant, he will work with senior partners Tony Danaher, Sue Brown and Dominic Morgan.
Roberts expects to work with existing clients Stanhope Plc, Insignia and Tesco, but will also be charged with attracting new business.
Tamesis, which has never had a dedicated corporate specialist before, aims to tap into what it describes as a burgeoning corporate market.
Roberts said: ‘They needed extra heavyweight help and that is what I bring on board.’
Roberts joins a company that currently numbers 30, including a second office in Manchester. He expects to recruit new staff.
The appointment was made following approaches by Tamesis through ‘a mutual contact’.
In his role for KPMG Roberts led a team of six and drew up the company’s international PR strategy, covering a £1m budget.