But Diamond, a senior fellow at Stanford University’s Hoover Institution, said small was better for the body that would put forward candidates for the first election of a chief executive by universal suffrage.

“It is better to have a small nominating committee that is capable of putting forward a genuine alternative candidacy for chief executive than a large body more or less like the current one that is not capable of doing so,” he said, elaborating on his idea to the South China Morning Post.

Echoing the views of former civil service minister Joseph Wong Wing-ping, who also suggested constituting the Legco as the nominating committee, Diamond said in a written submission to HKU that a low nomination threshold – of 10 to 12.5 per cent of the committee– would neutralise the over-representation of functional constituencies in the legislature.

Chan said it could be argued that a smaller committee was more susceptible to manipulation.

“Yet the opposite is equally true,” he said in an e-mail reply. “Small committee means you need only a smaller number to reach the threshold and this is easier to achieve.”

Chan was the first person to break new ground over the reform debate when he proposed a 160-member nominating committee including all lawmakers.

He said his plan was more balanced than Diamond’s as it also included directly elected representatives and members from the National People’s Congress and Chinese People’s Political Consultative Conference.

But Chen said he believed proposals to broaden the electoral base of the existing election committee – including those by Civic Party Ronny Ka-wah and himself – were more likely to be considered consistent with the legal framework.

Meanwhile, Diamond also suggested adopting a preferential voting system – which allows voters to rank their choices instead of picking the winner through a simple majority – as this might ensure the winner would not come from either end of the political spectrum.