The school closed in 2006 because students with hearing impairment were put into mainstream schools as part of the government's push for inclusive education. The site was later earmarked for vocational training purposes. The Education Bureau invited three vocational training providers, including the FTU, to set up a training centre there without going through public tendering.

Education legislator Cheung Man-kwong said a uniform allocation process by public tender was needed as more school sites in prime areas became vacant, with falling enrolments forcing schools to close.

'There will be more and more vacant school sites situated on prime property up for grabs in future due to the wave of school closures,' he said.

'To remove suspicion of favouritism towards government-friendly organisations, there should be more transparent mechanisms dealing with the apportioning of vacant school sites. The government should also make it known that the public can apply for the sites. Otherwise, no one will know they can apply for them.'

The FTU, the city's biggest union and a government ally, holds four seats in the legislature and is considering becoming a political party.

Its Employment Development Service, a registered charity, started operations in November last year after renovations helped by a HK$10 million grant from the Jockey Club. Employment Development Service vice-president Leung Kai-lik said the charity applied for a venue in 2007, soon after it was set up, and was later given two to three sites to choose from. 'We didn't specifically ask for the Tin Hau site,' he said. 'We just needed a centre for running training courses after we set up the charity arm in 2007.'

A senior pastor with North Point Baptist Church, one of the other charities, said it was unfair it was excluded from the application. 'Both the HKFTU and us wanted to run the site for training purposes,' pastor Ng Kai-wai said. 'We wanted to run an education centre for old people as Tin Hau is a place which is affected by the ageing population,' he said. 'Charitable organisations that wanted to develop the site for education purposes should have had an equal chance in competing for the site.'

Eastern District Councillor Dr Jennifer Chow Kit-bing said many organisations had asked her about the site due to the location. 'It was given to the HKFTU shortly after the deaf school was closed. There was no fair chance for others to compete for this piece of golden land. There should be a transparent bidding mechanism.'

Another vacant school that was given to a charity without public tender was Hong Kong Weaving Mills Association Primary School in Mong Kok, which was closed in 2008 because of falling enrolment. Situated on Prince Edward Road, the site is now an education centre run by the Weaving Mills Association.

Yau Tsim Mong district councillor Law Wing-cheung said he was angry when he got a government notice in 2008 saying the site had been given to the association.

'There was not any public consultation. It's prime property situated in the city centre. If the organisation who got the site paid market-rate rent, I wouldn't object at all. But they are paying nominal rent as a non-profit-making organisation,' he said.

Law said many organisations in the district would have been interested in bidding for the site. 'As a lot of public money is involved, there should be an open tendering system that allows others to participate in the bidding process. When I lodged my complaints with the government, they said the lease would just last one year and the site would be returned to the government. But the short-term lease expired last year and the education centre is still running.'

Education Bureau figures show that 92 schools ceased operation over the past six years. Of the 92 vacant sites, 49 have been redesignated for educational use and, of those, 19 are already in use. The other 43 sites which were deemed unsuitable for education for their 'limited size and remote locations' are under the jurisdiction of the Lands Department.

A Lands Department spokesman said interested parties could apply to use vacant school premises.

The Education Bureau, which is in charge of allocating the 49 sites earmarked for education use, said it would invite applications from eligible organisations once educational use of a premises was confirmed.

'Quality of education will be the prime consideration in assessing applications,' a spokeswoman said. 'The HKFTU was selected on the basis that it is a non-profit-making organisation with abundant experience in vocational training.'