I may also turn the comments on and off on that post as I try to get rid of his comment - just in case your over for a look!
It's one of the perils of blogging.
Update: checked the blogger help group and others are reporting this issue over the last few days - again chinese spam.
Update: it seems it was possibly Korean rather than Chinese SPam that I got hit with from reading the blogger help forum. After trying numerous ways of getting rid of the spam comment the only method I could find that worked was to copy the original posts and the non spam comments to a new post, delete the original and then reset the copy back to the original date. Blogger would appear to have a vulnerability that is being exploited by this particular Korean spammer. He or they appear to have found a way to prevent their spam comments on posts being deleted.