As from today (1 October 2011), the Patents Rules 2007 are amended by The Patents (Amendments) Rules 2011 to correct a drafting mistake. Time periods in the Rules that were defined as "beginning with" a particular date are now to be defined as "beginning immediately after" that date. These changes have been made apparently in light of Rigcool v Optima Solutions, which concerned the correct way to calculate the two year period for initiating entitlement proceedings under Section 37(5) (although this period is not being being altered by these changes). The resulting anomaly in how the Rules were interpreted was noted in my post on the subject here.
The changes, which are numerous, have already been made in the (unofficial) version of the Rules available on the ukpatents wiki. One small point to note is that these changes are not a straightforward find-and-replace job, as there are some places where the old wording is maintained, such as in Rule 18(1) where both the start and end of the relevant period (ironically relating to missing parts) are defined.