Cyclists like you make people like me vote against pro-cyclist laws. You have no moral right to slow down all traffic on a road to the speed of your calves because you feel unsafe in your designated lane, and I hope you soon have no legal right to do that.
You forget that most often such a lane is as wide as a bicycle + 10 cm on each side. Meaning that if a car passes fast enough it could even push the cyclist around just with its air flow. Plus, at lower speeds bikes tend to go less than straight, so there is a fairly real danger of bumping into, e.g. the mirror on a car. Additionally a cyclist is obligated to handle things coming at him from between parked cars and such, which is really tricky since a cyclist is often much closer to those than a driving car. Those and more i don't have in mind right now are plenty important reasons why taking a lane can make traffic safer for everyone.
Having been in the situation often enough, i can also tell you: I wouldn't mind if cars passed by me in narrow situations if they slowed down while doing so, but more often than not, cars pass by at full speed instead.
Lastly, keep in mind that this situation only happens in narrow side streets, not on big streets with better separated traffic flows.
Sport cyclists taking a whole lane while ignoring a dedicated bike path are just assholes.
In the UK, highways are for the public to use. No preference or priority is given to any vehicle user or person wishing to use the road faster. I am not slowing down traffic, I am simply using the road as is my entitlement. There is no law which states I must travel at a minimum speed, nor one which requires me to use any particular part of the lane I use. Within sensible use and reason, I use the lane how I see fit.
There are of course provisions to dissuade or prevent vehicular use which is purposefully obstructing, but my purpose is not to obstruct. Its purpose is to aid in the enforcement of rules which state vehicles must pass cyclists within certain safety limits, which they do not adhere to of their own.
I have a moral right to not be killed by impatient people. I do not just "feel" unsafe in my designated lane: I am unsafe. Cycle paths, in the UK, are not mandatory for any users, precisely because they are not always suitable. Until the UK's highways are no longer for the public there will never be a time where I am not entitled to safe passage on it.
