R (on the application of Mercury Tax Group Limited and another) v HMRC and others  EWHC 2721 (Admin)
Although this is a tax case dealing with the validity of a tax avoidance scheme, it has some interesting things to say about the execution of contracts in general, and the execution of deeds in particular.
Mercury Tax Group: The court had to look at two practices that are undoubtedly common in the construction industry: parties executing signature pages before final agreed version of the contract is available and, alternatively, a new version of an agreed contract being created (for example, where a mistake has been found in the original) and signature pages attached to the old version being physically transferred to the new version. Both practices were disapproved of in this case. In the case of a deed, the court noted that these practices would invalidate the deed due to s.1(3) of the Law of Property (Miscellaneous Provisions) Act 1989, which requires that the signature and attestation form part of the same physical contract which constitutes the deed.