'We set ourselves a budget of about HK$3 million ... To help get things started, I contributed 10 per cent,' he said. As the treasurer of challenger Alan Leong Kah-kit's campaign, he later paid other upfront costs for the launch and contributed HK$345,810 in total, the biggest amount by an individual in the chief executive election.

Mr Cautherley is managing director and a shareholder of the HCD Holdings Group, which specialises in manufacturing, marketing and distributing medical products. Another biotechnology research firm he runs, R&C Biogenius, is receiving research funding from the government's Innovation and Technology Fund.

'I'm not a tycoon. There is no political fallout as far as I'm concerned. If you believe in something, you should step forward,' he said.

Mr Cautherley has financed The Frontier and the Democratic Foundation's operations. But this was the first time he had funded an election campaign.

Asked if his funding for Mr Leong's war chest would upset Beijing and the government, he said: 'If I was donating to 'Long Hair' [lawmaker Leung Kwok-hung], maybe there is a difference.

'In my field of business, I am not involved with people who might think what I was doing was unpatriotic or offend China. I have had no adverse feedback so far. And I don't expect any. It wouldn't deter me from contributing next time either.'

He said Beijing and businessmen need not worry, as Mr Leong's platforms were rational.

'I think there must have been some reassurance to the central government that when the democrats put up a candidate, they would come up with sensible policies.'

Mr Cautherley believed the introduction of universal suffrage would push up the campaign expenses ceiling, now capped at $9.5 million, raising more financial pressure for the democrats to run in chief executive elections in future. Mr Cautherley, who will be 65 in September, said he was confident he would see universal suffrage in his lifetime.

He criticised Mr Tsang for an 'underachieving' attitude in the fight for universal suffrage.

'I don't subscribe to Donald Tsang's view that you should know what can or cannot be achieved,' he said. 'I think if you adopt that attitude, you would always underachieve.'

With the government due to issue a green paper on universal suffrage this year, Mr Cautherley, who helped arrange a dinner for former chief secretary Anson Chan Fang On-sang and the democrats at the Hong Kong Club last month to iron out their differences on the preferred model, said they would resume talks soon.

Political pioneer

Alan Leong was the first member of the pan-democratic camp to contest a chief executive election

Total amount (in HK dollars) of donations he received for his campaign $3.8m