Had a few like that recently, going down a hill in third doing about 30-35 the limit is 30, and this red escort van is sitting right on my bumper, its late at night so there is nothing coming the other way, i even moved over to give them even more space, but no, he likes sitting behind me.
Round a few bends, on a perfectly straight bit of road, 35 he's still right there, so i take my foot off let it slow down, by this point i am doing 20 and he is still sitting there! i have to indicate before this moron will get past me.
And as you said, he didn't go much faster once he was past.
I wish they would grasp the concept to go faster than me they have to go around me, not through me.
Same thing again in the same place a couple nights later (loadsamoney will know where i mean, i think its the road past his house) another idiot in an A4 with only some R8 style fairy lights on and nothing else, he eventually back off and stayed a good way back.
Coming up to christmas the standard of driving has dropped dramatically.