Civil Partnership Act and Gay Marriage?

The Civil Partnership Act 2004, which allows gay couples to register their relationships legally, comes into force on Monday. The General Register Office has just sent out a letter to ministers like myself who conduct weddings. It is headed ‘Changes In Terminology In Marriage Registers’. It states that ‘Civil partnership will be a lawful impediment to marriage’ (and then goes on to lay out new terms that must be used to describe a person’s ‘condition’ at the time of marriage). Isn’t this a bit rich from a government that has told us that civil partnership is not the same as gay marriage?