According to Erskine May, an 1851 manual of parliamentary practice in the UK, the practical advantage of King's Consent was that it enabled the crown to protect its rights without having to resort to blocking a bill after its passage by refusing royal assent. More recently, however, there has been criticism of the crown being consulted on the content of forthcoming bills, and "given the right and opportunity to shape prospective legislation".[1] Critics allege that even though the crown may never formally withhold its consent contrary to government advice, the procedure is nevertheless being used to vet and change draft bills before they reach parliament. One report noted that it was "almost certain that some bills were changed before introduction in order to address concerns about crown consent".[2][3]