Spoilers

Here are the Digital Spy spoilers but 3 of them are fake:
Doctor Who's fourth season is back on track with this fabulously delicious slice of murder mystery and insect intrigue. A fine ensemble cast, including Felicity Kendal, and the wonderful use of the 1920s period setting ensure a fun, thrilling romp of an episode. In particular, a certain death-defying scene set in a kitchen may well be the funniest in Doctor Who's 45-year history. Here are a few hints about what lies in store, including three fake spoilers...

Donna tries to blend into the time period by saying "spiffing" and "chin chin".

There are spinning newspapers.Fans of Cluedo will love the pre-credits sequence.Agatha

Christie makes a s*xual advance towards Donna, but is loudly knocked back.

An arrow-armed Doctor is seen in flashback in Hercule Poirot's old hunting ground.

The Doctor tries to down a jar of anchovies.

Part of a Cybus Cyberman turns up in the episode.

Donna thinks that 'Murder On The Orient Express' is a song by Sophie Ellis Bextor.

There is an explicit reference to the events of 'The Unquiet Dead'.

Donna tells Agatha Christie that her plot twists are nothing compared to the Jeremy Kyle Show.

The Doctor disappoints Donna by telling her that Enid Blyton's Noddy is not real.

Chief Inspector Smith from Scotland Yard makes an appearance.