Well, good for him. We don't need any changes to copyright law in this country particularly when it is likely to be of disbenefit to the original author....
This issue has been debated at length on American forums and also been the subject of a detailed analysis in the BJP. The universal consensus is that this is basically a ploy to reduce copyright protection and almost certainly any institution in the UK that usurps the rights of any American copyright holder will be be subject to litigation in the American courts. It seems the same will be true if any EU photographers have their rights infringed as they are protected under EU and national laws. The govt seems to be saying, in effect, that if something is 'lost' it becomes the property of the finder....and, the finder is not obligated to try too hard to find out who the owner is. In fact any institution or business can use any image that is not blatantly copyrighted and claim 'ignorance' of the authorship of the work...knowing that if the author ever discovers the illegal use there will only be a token 'penalty' payable.