When the University of Cambridge, with help from the University of Sussex (and JISC funding), released its Newton Papers, there was widespread acclaim for the resultant website, but also some criticism of their use of Creative Commons.
It seems a common sense argument, but this ignores the actual state of UK and the complexity of digitising fragile material.
UK Copyright law implies that digitised images can create their own copyright, if the digitisation is of high-quality.* A quick snap with a cameraphone of an ancient document does not accrue copyright; but a complex procedure involving conservation, handling, colour calibration, adjusting lighting conditions, careful focussing does create copyright in the resultant digital image. The contextual infrastructure to actually deliver the Digital Library also required serious investment of time and money.
Thus in the case of Newton Papers, Cambridge do have a right to assert Creative Commons over their digitised versions of the papers.
It also should be noted that the Cambridge licence used is still very liberal – as long as you don’t make money from it and attribute the source you can use it in any way you want, including creating derivative images. A few years ago, it was a very rare university that would have gone near such an open licence.
* However, it should be noted that this implication has never been tested in a UK courtroom. It was tested in the USA (in the Bridgeman Art Library v. Corel Corp. case), but the result in favour of Corel is not binding in the UK. The dispute between the Wikimedia Foundation and the National Portrait Gallery is also interesting in this respect.