So here you are, cycling along Kennington Park Road - aka the A3 - northwestish towards the Elephant and Castle.
You want to turn right at the lights just in front of Kennington Underground station, into Braganza Street.
So you take the centre of the lane and signal.
When the lights change, you wait for a gap in the oncoming traffic to turn right.
There's a clear sign at the left saying the bus lane only works in rush hour. This junction is clogged with cars, buses and fluorescent cycle commuters in rush hour. But this is outside rush hour, on a Saturday lunchtime, so straight-ahead traffic is perfectly at liberty to use the bus lane to pass you safely. And there are no buses in sight.
The observant driver would see the sign and do just that. And the unobservant but patient driver would wait calmly while you turned right, just as they would for a car.
Sadly, the observant driver in London must have been away for the weekend with the unobservant but patient driver. At this junction, cyclists waiting to turn right get passed at speed dangerously close, hooted and sworn at.
It's a sad illustration of several things.
First, driving in London is not easy. There are a lot of road signs to read. An average copy of the Sun probably has fewer words than the amount of roadsign literature the driver has to read every minute.
Second, bus lanes change their exclusion of cars from 24-hour to rush-hour only abruptly and inconsistently, you can be fined £120 for driving in one when you shouldn't, and you can understand drivers erring on the side of financial caution and staying out of them when in doubt. Though they rarely seem in doubt as to when to use the horn.
But third, it also shows just how impatient, rude and dangerous some drivers get behind the wheel. No matter that your manoeuvre is quite legitimate; no matter that they can't read simple road signs. You're in their way.
Anyway, if you do manage to turn right unscathed here, we recommend the No 1 Off Licence. The guys in there are friendly and always having good-natured banter about football, and after your experiences you might need a can of something.