Griffiths and Lytton were captured by the Cybermen hiding in the London sewers and were taken to Telos in the 27th century. They escaped and met up with the Cryons, who he learned were his and Lytton's actual employers. They went to the surface of Telos where they met up with Bates and Stratton. While attempting to reach Cyber-Control, Lytton was recaptured and Griffiths, Bates and Stratton were shot and killed by a Cyberman. (TV: Attack of the Cybermen)
Behind the scenes
In the novelisation, his full name is given as Charles Windsor Griffiths.