This is where i think peoples understanding of the highway code is not quite as great as they make out (given some of the "cyclists" responses in this thread)
never ride more than two abreast, and ride in single file on narrow or busy roads and when riding round bends [section 66]
yet at least three people have said riding 2 abreast is the right thing to do.
guess everyone's an expert if it suits their opinion...
We went over this at the start of the thread.
The Highway code is clear that cycling two abreast is perfectly fine and legal. However, some people who have passed a driving test seem to be unaware of this and think the Cyclists are doing something they shouldn't, which is where the main part of this problem stems from.
The second part of the that section of the code though which refers to going single file is somewhat of a variable based on the road and situation.
If Cyclists riding two abreast were causing a tailback for miles, which as many have already pointed out is such an unlikely occurrence, and something I've never really seen. Then yes, that would be selfish and they should adhere to the code and move single file.
In other situations though where the road isn't so busy, as has been pointed out above, you need to treat overtaking a cyclist the same as a car, this is something you are taught in order to be a licensed motorist.
Take a country road for example which is quite narrow, if the Cyclists are two abreast, the motorist has to treat it like a car and wait until they can make a safe pass. Riding single file though could put them in danger because a motorist may make a dangerously close pass at high speed, which is further exaggerated coming towards a bend or if there is oncoming traffic. If however the Cyclists are on that same road with 25 cars behind them, then they certainly should allow the vehicles by if safe to do so.