Political gimmick, but I remember the petition for this was posted here & I guess this apology was prompted by that campaign.
When I read it I just thought it was a nice thing to do.
Either way, due credit for making the statement.
http://en.wikipedia.org/wiki/Conviction_of_Michael_Shields#R...
"... I have recommended to Her Majesty the Queen that he should be granted a free pardon and she has graciously assented."