Fundraisers have pledged £6.8m towards the Oxford Children's Hospital.

With £5m of NHS funding already promised, organisers are more than half way to their £20m target. Work on the hospital is due to start on the John Radcliffe site in Headington next year.

The donations mean the Oxford Radcliffe Hospitals Trust has more than half the £20m cash it needs to construct the three-story unit at the John Radcliffe Hospital in Headington, which has already been awarded £5m of NHS funding.

The announcement came as the Oxford Radcliffe Hospitals NHS Trust revealed that the Radcliffe Infirmary had been sold to Oxford University for more than £40m. A confidential report said the trust had expected to get £29m.

Money raised will be used to clear £20m debts incurred by the trust, and for further investment by Thames Valley Health Authority. The university will use the site for teaching, research and student accommodation, though as part of the deal, Oxford City Primary Care Trust could also buy a quarter of the 10.5 acre site to develop a health centre.

The trust's outgoing chief executive David Highton and chairman Neil Ashley were on March 26 celebrating the progress made in raising cash for the children's hospital, with appeal campaign chairman Dr Paul Drayson, by building a pyramid of building blocks for every 1m pledged so far.