Sunday GIRL

The Doctor teams up with UNIT to investigate what happened the night Ruby was born

- STEVEN PERKINS

SCI-FI Doctor Who Saturday, 6.30pm, BBC1

Ever since Doctor Who viewers were first introduced to Ruby Sunday on Christmas Day last year, there's been a big question mark surrounding her birth. She was found abandoned as a baby on a church doorstep, but who left her there - and what happened to her birth parents?

In this week's episode, The Legend of Ruby Sunday - the first episode of a two-part finale - the Doctor (Ncuti Gatwa) and Ruby (Millie Gibson) team up with their friends at UNIT to investigate what happened the night Ruby was born. However, a terrifying evil is unleashed in the process.

Fortunately, the pair have some of their closest UNIT allies at hand for the fight ahead, including Kate Stewart (Jemma Redgrave) and the Doctor's former companion Mel Bush (Bonnie Langford).

'I was in the show 37 years ago, and I would never in my life have thought I'd be back, Langford tells TV & Satellite Week in an exclusive interview. 'But it's very nice to be able to come back to a Langford character who I always felt was unfinished - or probably unstarted, really. Mel didn't even get a beginning story!'