Cyclists who ride in the middle of the road (30cm from the kerb i thought it was), even worse is cyclists who ride side by side on country lanes.
Er - back to the Highway Code for you!
They're (it is "they're" - I don't want to resurrect an earlier post) taught to ride at least a metre away from the kerb, and more at pinch points. The thinking is that they dissuade people from squeezing through a marginal gap.
...and if you're leaving as much room as the Highway Code says, which is as much room as you would for a car, then two abreast makes them
easier to pass because the joint overall length is shorter. According to the good book, they must not be more than two abreast.
Don't flame me. I'm not going to defend every cyclist any more that I'd defend all GTI drivers. I might ride a push bike from time to time, but motorcycles, HGV (class one), PCVs and Mk5 GTIs much, much more!