Bill and the two Doctors escape from one Tardis to another in new clip from the Doctor Who Christmas special

After two trailers and a meaty scene between Peter Capaldi's Twelfth and David Bradley's First Doctors, here's a new clip which gives us longer with Pearl Mackie's returning companion Bill Potts and includes her first glimpse inside an older version of the Tardis, complete with smaller windows...

Doctor Who: Twice Upon a Time airs on BBC1 on Christmas Day (Monday 25th December) at 5:30pm