Thanks, many of the replies have been helpful and many of those that were not were at least humorous.
To clarify my earlier post, my main motivation for doing this is to make my girlfriend happy. We have both agreed we want to get married. She likes the thought of me including her Dad in the process, mainly because it shows him the respect she believes he is entitled to. I have no issue with this.
That being said, the reality is probably closer to the fact that her Dad is a control freak and would resent not having some say (if only imagined) in the matter. If she did not ask me to do it, I would like to think I would still do it as a means to flush out any issues sooner rather than later.
If he does not offer his blessing then we will need to consider the implications for the marriage. In that situation I think my girlfriend needs to decide whether it is an issue.
For Dad's out there, what is it your looking for before providing a blessing? Part of me believes that there will always be a natural conflict between a father-in-law and son-in-law, but that there is a medium to be reached.