DIB said:
TTSS got a good review in Uncut mag this month. It will be interesting to see how Gary Oldman's George Smiley compares with Alex Guinness. He seems (to me at least) possibly too young for that role?
John Le Carre' himself had to be quite 'fluid' about George Smiley's age (especially between the first GS books like 'Call for the dead' and 'A Murder of Quality' and the later trilogy starting with Tinker Tailor Soldier Spy).
Essentially he was old enough to have graduated and be trained by the SIS and working in Germany (building a network) in the years immediately prior to WW2.
I would estimate GS being born around 1915 - 16 and being around 57 - 58 years old at the time of writing of TTSS (published in 1974 but probably written around 1972-73). This was a reasonably good 'fit' with Alec Guinness, who was born in 1914 and was 64 when the TV series was being filmed.
Gary oldman was born in 1958 so he is already 53 years old. I don't know (yet) if the movie is faithfully set in the early 1970s or has been 'shifted' but if it is set (like the book) in the early 1970s then Gary Oldman only has to 'gain' around 5 years in the makeup room.
So basically Alec Guinness was around 5 years older than the character of George Smiley and Gary Oldman about 5 years younger.