Merry Meet FeowFeow,
Well with regards to local legislation according to UK Defamation
Act 1996, he is liable for Defamation, Libel & Slander
especially through such avenue & platform!
Below is the Excerpt of Singapore Law:
Singapore's law of libel protects all
persons against unjustified attacks on their reputation. A person
is libeled if the words expose him (or her) to the risk of being:
hated, ridiculed, or viewed with contempt, or shunned or avoided,
or lowered in the standing of right thinking members of society, or
discredited in his trade, business, office, or
profession.

Blessed Be,
Oceanos