Simple question, complicated answer... but there is no risk of this. NT do not own the photos, the photographers do, even if they were trespassing. Alamy, as with any agency, asks photographers to warrant the status of submissions (as model/property released or not + their own copyright) and then protects itself via T&C's that hold the photographer liable. Unreleased images are only offered for editorial use. For an ad campaign requiring NT endorsement or merchandising, the buyer would, unless they are daft, ensure the release status meets their needs before purchase. If the photographer lied the buyer would have a claim against Alamy not only for refund but also any costs incurred, but Alamy would hold the photographer liable under contract. The photographer also might possibly be open to a criminal case of fraud. All the stuff in the next par. applies too... The buyer would only incur liability if they proceeded without getting rights sorted. Then NT might have a civil case against them for defamation, depending on the context of use. Alamy would not be in the frame, but they'd no doubt sever representation of the photographer and be able to sue for breach of contract terms if they had any losses to recover. For editorial use, no liability would arise for the buyer. Again Alamy would hold the photographer liable. NT could possibly do one or more of the following to the photographer: - try and bring a criminal prosecution under byelaw - sue for trespass and claim damages, - try and enforce their contract terms and claim damages - contest IP ownership. This is pretty weak given the absence of copyright in buildings, but in some circumstances the courts have assigned economic copyright (the rights to all income) to a plaintiff whilst acknowledging that author's copyright and associated moral rights belong with the creator. None of these are likely to be worth the ink, let alone a lawyer's time because editorial rates are puny amounts of money. Property releases are widely used to try and avoid this sort of mess but there is no reason to believe they have any validity in UK law. It's different in USA because of copyright on recent buildings and certain others and the existence of statutory damages for registered copyrights (up to $150k). Here the legal rights of landowners are defined in common law, damages are limited to provable losses, and any contract that goes beyond that is open to challenge as unfair. The NT insists you need a property release for any commercial use (in the broadest sense of 'commercial'). I've never seen one so I don't know what it says, but it's not unlikely it's either redundant or unenforceable. Basically they're just granting permission for photography in exchange for some money, as far as photos are concerned. Expensive problems will arise if the buyer publishes trademarked logos or other IP of NT, and/or makes false claims of endorsement. But NB I am not a lawyer and this is not legal advice.