This is an observation based on watching HARDtalk for many years starting from the time when Tim Sebastian was performing the role now taken up by Steven Sackur.
My comment relates to the present incumbent Steven Sackur.
When a person from Eastern Europe, South America or Asia is being interviewed Steven Sackur is very aggressive and speaks in a demanding and overbearing tone. On the other hand when he speaks to a North American like David Beaseley he is much more polite, sweet and almost submissive.
This is just an observation and I am not making a judgement about whether it is right or wrong.
Please treat this simply as feedback based on observation.