Britain is not putting enough pressure on China to stick to its side of an agreement on the transfer of Hong Kong's sovereignty because it is worried about damaging trade links, former Hong Kong Gov. Chris Patten said on Tuesday.

China took back control of the former British colony in 1997 through a "one country, two systems" formula that allows wide-ranging autonomy and specifies universal suffrage as an eventual goal.

But Beijing said in August it would effectively screen candidates who want to run for city leader, a decision that has prompted weeks of street protests by prodemocracy activists who said it rendered the notion of democracy meaningless.