Raedwald has some interesting suggestions on what to do with them.
As a cyclist with many thousands of cycle-miles under my belt, I feel as obliged to preface any remarks on my less-responsible brethren with the sort of disclaimer that used to be compulsory for any criticism of immigration. During my lifetime cycling has seen an astounding increase in special provision, from cycling lanes (which are mostly crap and don't work) to cycle boxes at lights (highly effective in giving nervous cyclists the balls to wait in front of an artic)
However, I've also seen the rise of a most unattractive 'militant' cycling - and it's mostly the arrogant young and wealthy who can afford to waste thousands on risible clothing and footwear and inappropriate bikes who are responsible. Riding a bike isn't an excuse to break the law, be aggressive to other road users, selfishly ignore the well-being of pedestrians or to cause general public alarm and dislike of those of us who do none of the above.
As cycling has come of age as a legitimate and competing transport mode, so the policing of cyclists should evolve. Extending the powers of PCSOs to stop and fine cyclists, and putting a few thousand of them on cycles, should do the job. And for repeat offenders - yes, including the broker-boys of the square mile in their £500 cycling shoes - jail. Poland has over 4,000 cyclists in jail for drinking and cycling. We don't need to match this. A few hundred wealthy young boy racers doing six months in prison should do the job.