Extract from an interview by John Porter
TV Zone 62 (Dec 1994) p32-34
Blake's 7 was a one-off appearance, but in Space: 1999 Michael was originally scheduled to play a regular character. However, things didn't quite work out as planned. "The idea was, when they put it all together, they were going to have this group of people who got blown off into space. I was going to play one of this group of assorted characters, as were several other actors."
"However, they found that if all these characters were going to be in every week as regulars, there was going to be no time for Mr and Mrs Landau to have any screen time at all. So around the third episode there was this enormous explosion and most of us got blown up. They got rid of half the cast. However, some episodes later they found this starship floating about in space [Dragon's Domain], and then they went back in time and there was yours truly. So I came back, briefly. We did it up at Pinewood, and on the first day they gave us those beautiful costumes. They were of a woollen consistency, and when the ladies put them on it was found that strategic sticking plaster was necessary. It was felt that they shouldn't be seen to be protruding too much in what was, after all, a children's programme.'
Sheard's explanation is basically correct, although the details are inaccurate. As we all know, the explosion was in episode one, not the third episode. Sheard filmed scenes in Breakaway as a character named Gundlach (you can hear his cut scenes here). He was employed for a single episode, not with a series contract. If Sheard's role had been larger (and not cut in the final edit), he might have been asked back.