Review of all 4 episodes:
The Doctor and Jo have a rare adventure away from contemporary Earth as The Doctor manages to take the TARDIS on a 'test flight' and they end up on the planet Peladon. The Doctor is mistaken to be the Earth delegate of a committee from the Galactic Federation and is made chairman of the committee. Jo is believed to be an Earth princess. The task for this committee is to assess Peladon's application to join the Galactic Federation. This is all an allegory for the UK's accession to the European Common Market (which became the EU) which was a big issue at the time.
A legend of a monster and strange incidents begin to threaten proceedings and there is a mystery surrounding who or what is behind the apparent attempts to stop Peladon from joining the Federation. The other committee members provide varying, interesting alien species. The efforts to create these unusual aliens is to be admired and it is surely the clear inspiration for a very similar scenario in the second episode after Doctor Who returned in 2005 'The End of the World'.
One of the alien delegates, Alpha Centauri, may seem slightly annoying and somewhat lacking in credibility to a modern viewer but the effort to make it a very different life form (as they tried valiantly but unsuccessfully in 'The Web Planet') is highly commendable. The other aliens are interesting and well realised with the Ice Warriors providing a nice twist on previous stories where they featured.
The script from Brian Hayles is very well written and intelligent with nice political undertones. There is plenty of fun and action and some very good performances, particularly from previous Doctor Patrick Troughton's son David as King Peladon who is excellent.
Jon Pertwee is superb as the Doctor and Katy Manning is very strong in this story as Jo. Ice Warrior delegate Izlyr is very well performed by Alan Bennion.
It is not perfect with the hypnotism and its effects being my least favourite aspect but it is all highly entertaining and intelligently written with plenty of fine acting.
My ratings: Episodes 1 & 2 - 9/10, Episodes 3 & 4 - 8.5/10, Overall 8.75/10