By James Pomfret and Jessie Pang HONG KONG, Feb 9 (Reuters) - Hong Kong's most vocal China critic, media tycoon Jimmy Lai, was sentenced on Monday to 20 years in jail, ending the city's biggest national security case which drew international concern about Beijing's clampdown on the city's freedoms.

Jimmy Lai, Hong Kong's pro-democracy media tycoon, has been jailed for 20 years for colluding with foreign forces under the city's controversial national security law.

Last month, Lai was convicted on two counts of conspiring to collude with a foreign power and one count of conspiring to publish seditious materials through his media group, the now closed pro-democra...