If I buy a site with planning permission, can I use the original architect's designs to develop the site?
If an architect is engaged by the site owner to produce designs to obtain planning and you buy the site from that owner, then in the ordinary course of things the answer should be yes. The relevant case is Blair v Osborne & Tomkins  which states that as long as the original architect gets paid, they are deemed to grant to their client an implied licence to use their drawings and designs for the purposes of building out the development. This implied licence is freely transferable to purchasers, so a developer buying the site from the original owner should make sure to obtain an assignment of the benefit of the licence as part of the deal to acquire the site.
The architect's consent is not ordinarily required for such an assignment. The architect still owns the copyright in their drawings and designs, unless their professional appointment goes further and requires the architect to assign ownership of the copyright to their client.
The recent case of Signature Realty v Fortis Developments  EWHC 3583 involved a claim for breach of copyright made against the developer of a site (Fortis) by another developer (Signature) whose architect had produced designs used to obtain planning permission for the site. The Court decided that, in part, Fortis was liable for breach of the original architect's copyright, ownership of which had been assigned to Signature.
The case was unusual though, in that the claimant developer Signature had engaged its architect to produce designs, and obtained planning permission, in relation to a site which Signature did not at any stage own. Fortis bought the site not from Signature, but from the site owner who had been in negotiations for the sale of the site to Signature but got fed up with their inability to put forward the purchase money to complete the deal. So there was no scope for the benefit of the copyright licence to be assigned from Signature to Fortis - they were not in a contractual relationship at any point. Fortis could have sought its own copyright licence from the architect, but evidently did not realise they needed one.
Once the planning application drawings had been uploaded to the local authority planning portal they were available to be used by anybody, for the limited purposes allowed by the copyright notice on the portal, and subject to the original architect's assertion of copyright ownership on the face of their drawings. Fortis were only liable for copyright infringement because they either ignored or did not understand these restrictions and copied the original drawings in their design for the completed development.
Fortis could have better protected itself if its advisors had carried out appropriate due diligence and reported on the potential copyright infringement that was likely to occur if Fortis proceeded with the development using the planning permission drawings without the original architect's consent. Alternatively, Fortis could have sought a new planning permission, or obtained the original architect's permission to use the drawings, presumably for a fee. The question a developer should ask in such circumstances is: who owns the copyright?
This article first appeared in the Professional Housebuilder