This continues a run of tremendous top quality stories. The majority of the episode is subtle in its qualities but is unquestionably excellent throughout in my opinion before reaching an electrifyingly exciting last 10 minutes as at the end it re-introduces one of the Doctor's greatest enemies in the most thrilling way.
The writing of the whole episode by RTD is brilliant with an engaging script which has humour, intrigue, touching drama and dystopian futuristic ideas.
Derek Jacobi, one of the great actors of our time, puts in one of the best guest starring performances in the show's history. The full range shown by Jacobi as he portrays different sides of the character is sensational. He is beautifully endearing before building towards very moving moments as he struggles with memories hidden deep inside and then a dazzling different side is shown in the heart thumping final scenes.
David Tennant shows yet another awesome display in his top standard performance as the Doctor, Freema Agyeman yet again proves to be a perfect companion, John Barrowman makes a very welcome and impressive return as Captain Jack Harkness and all other acting, direction and production values are great.
Graeme Harper the director also directed 42 earlier in this series as well as the top 10 classic The Caves of Androzani from the 5th Doctor's era. He shows his quality yet again.
There is a nice link in to themes interwoven through the series involving the Doctor's watch in the wonderful Human Nature/The Family of Blood and The Face of Boe from Gridlock as well as leading on with the cliffhanger into the final two episodes that finish Series 3. (Utopia is generally accepted as being the first of a 3 part story with the following 2 episodes so I am going to have to go along with that even though I see this as quite separate).
The whole story, the acting and especially the terrific ending, makes this a top class cracker for my tastes.
My Rating: 10/10.