Old UK tv sci-fi series I'm trying to remember

I had this on video once and lost it...all I remember was it originally aired in England either in the late 70s or early 80s and was either about a planet that was knocked out of its orbit or on a collision course with another planet...I can't remember the frigging name of it :scratch: It's never been aired on the Sci-Fi (now Sy Fy) Channel. :(

http://en.wikipedia.org/wiki/Space:_1999

Is that it, by any chance?

Sounds like SPACE: 1999, but it's the moon. Just right for Mrs Aural Sects.

It wasn't Space 1999 (I should have specified that right away)...it also had a great opening theme. This one might be hard.... :pale:

Hmm, Star Maidens?

Gerry Anderson's UFO ?