Old Russian liberal originally obstructing court over son stabbing UK citizen (9)

I believe the answer is:

octobrist

I'm a little stuck... Click here to teach me more about this clue!

'old russian liberal' is the definition.
(Russian political movement)

'originally obstructing court over son stabbing uk citizen' is the wordplay.
'originally' says to take the initial letters.
'court over' becomes 'cto' (I can't justify this - if you can you should give a lot more credence to this answer).
'son' becomes 's' (genealogical abbreviation for son).
'stabbing' means one lot of letters goes inside another (some letters stab themselves into others).
'uk citizen' becomes 'brit' (a Briton).
The first letter of 'obstructing' is 'o'.
's' put into 'brit' is 'brist'.
'o'+'cto'+'brist'='OCTOBRIST'

Can you help me to learn more?

(Other definitions for octobrist that I've seen before include "Revolutionary" , "Moderate Russian" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app