Theophilus Tolliver

Theophilus Tolliver (who preferred to be called Theo) was a British inventor who invented a time machine in 1897.

During his second trip through time, he was captured by Andron, taken to 3550 New Britain and imprisoned.

After the Third Doctor was imprisoned with Theo, they worked together to escape execution and overthrow Mar-Kom. Afterwards, Theo returned to his own time, where he told his friend H. G. Wells about his adventures. (COMIC: The Eternal Present)

Behind the scenes

 * The implication is that Theo is the unnamed protagonist of The Time Machine.