THE biotech cluster specialist signed up five years ago to build the Edinburgh Bioquarter has cut its commitment to the park by one-third, raising fresh questions about the long-term vision for the project.

Alexandria Real Estate Equities of California, the biggest such operator in the US, has reduced its option to develop the site on the southeastern outskirts of Edinburgh from 924,000sqft to 636,000sqft.

Coming after Alexandria's decision to suspend its commitment to the park due to the economic crisis, it appears to further undermine former Scottish Enterprise chief executive Jack Perry's vision for a £250 million development creating 6500 high-end jobs.

The Sunday Herald understands some of the land covered by Alexandria's option was reallocated to the so-called bio-incubator, a £24 million office block for life sciences firms funded by Scottish Enterprise and the UK Government after Alexandria's suspension decision. The remainder was taken up by NHS Lothian for car parking for the new Sick Children's Hospital, due to be built in 2015.

A New York-based analyst who requested anonymity said that Alexandria was currently focusing only on the US, despite pressure to make good on international commitments, particularly in Asia.

Apart from the bio-incubator, which was completed several months ago and is now known as Nine Bioquarter, the rest of the developments at the 100-acre site have so far been public sector.

It is home to the Royal Infirmary, the Edinburgh University College of Medicine and Veterinary Medicine, and the university's new Centre for Regenerative Medicine.

The aim is to create a world-beating life-sciences cluster with particular strength in stem-cell research and translational medicine that will attract multinational inward investors

A spokesman for Scottish Enterprise said that Alexandria remains the development partner for the park, "but like almost all private developers in the current climate they are finding it difficult to take things forward".

He pointed out that three companies have announced tenancies at Nine Bioquarter this year, taking about 2000sqft of the 85,000sqft on offer. The bioquarter has also announced two collaborative partnerships with GlaxoSmithKline.

Alexandria could not be reached for comment.