The secret to filtering is take it easy. Keep your speed difference between you and the traffic low....that way you have a chance to avoid the twat that decides they want to kill you. If you don't miss them it shouldn't hurt as much.
I tend to keep the difference below 10-15mph. 1mph more is enough to pass. 50mph fly by's will kill you in the end.
And as Jo says its your own choice to or not to. But my argument is all riders should have it taught as part of the syllabus to allow that option.
I've only been riding a 3 months now, but commute through London traffic everyday on a baby Vara, and have been filtering from day one. Not much point in having a bike if you don't in London. My journey would take at least an hour longer if I didn't.
And the most annoying thing is drivers that speed up and undertake you. I mean seriously, even though I'm on a 125, you're going to have to stop in about 50ft, and I'm not. Why are you bothering? If you close that space, I'll only be past you a few second later. Plum!!
But from day one, I instantly hated scooter riders who will cut in at stupid places, such as when you're slowly approaching a traffic island, and they'll steam past you with only a couple of inches to spare. They tend to take stupid risks, am amazed I haven't seen one come off yet. Muppets.
But I'm doing my DAS in a couple of weeks, I'll specifically be asking if the test centre tend to expect filtering or not.
From when we spoke before Mr C about what school you was doing your DSA with and I told you that one of the schools test at Mitcham near where you live and there they like you to filter on Croydon Road from between the test center in Redhouse Road to the lights at Windmill Road and from the roundabout at Cedars Ave again to the lights at Windmill Road and on the Purley Way.