BBC/2Entertain ***

"IT sounds as if it could be cross tracing the time-space axis," says Nissa as a Concorde disappears off the radar and hurtles back through history.

"Better watch out for the odd brontosaurus," advises the Doctor (Peter Davison).

In Timeflight, the Master is back in the frame, monkeying about with such things as "exponential time contours" and "perceptual induction" while in Arc of Infinity the Doctor goes on location to Amsterdam to clash with the bullfrog-like Omega.

Both stories unfold entertainingly and are supported by a feast of extras, including Janet Fielding's reminiscences about her days as bossy Tegan (Mouth on Legs) Jovanka.