Further back in 1968 the Court of Appeal confirmed that if you… ‘have a motorcycle you are in the fortunate position of taking up so little road space that you can slide along the off side of traffic’ but, and here is the clincher, ‘because you are blinded to a great extent as to what goes on on the left-hand side of the road, you must… ride in such a way that you can cope with an emergency’.

The law on filtering is simple: if you do not breach any other rules, such as crossing a solid white line system or overtaking on zig zags before a pedestrian crossing then you may lawfully filter.

The law is equally as clear that if you choose as a motorcyclist to filter and leave yourself ‘blind’ as to what is going on to your nearside then if it all goes wrong you will attract some blame if you cannot stop for a foreseeable emergency. If you are zipping along the outside quickly you may be found entirely to blame.

Most filtering cases where a car emerges from a nearside junction on to a motorcyclist who is filtering result in an equal split of blame. Where a car driver throws an impatient U-turn into a filtering motorcyclist the motorcyclist usually wins.

Where a bike is whizzing along the outside edge of traffic at a speed which might be unexpected and a car emerges slowly through a gap in stationary traffic into the motorcyclist’s path the motorcyclist can be found entirely or largely to blame.

There is one judgment which found the motorcyclist wholly to blame but the Court of Appeal found this was limited to its own facts and involved a scooterist riding at 30 in a 30mph zone around the back of large truck, in rush hour and when a car emerged slowly from the back of the truck to turn right the vehicles collided.

The key point to remember is that when you, or anyone else, is moving into a bit of unoccupied road space it is no more yours than it is anyone else’s. All road users of all classes of vehicle have to anticipate other riders and drivers may drive or ride with less than perfection.

If two vehicles put themselves into the same bit of road, equally unsighted, then the law will hold each party equally to blame – so you filtering past a junction without considering the risk of a car nudging out into the road is just as culpable as the driver nudging out without considering the risk of you filtering. Both acts are equally as foreseeable, both are contrary to the Highway Code and unless one party is doing something which greatly aggravates the situation – speed is usually the aggravating factor – then an equal split of blame is almost inevitable.

Judges apply reasonable common sense to these cases and are rarely impressed by judgments from ancient cases. Basically you can filter, but do so carefully and be ready to pull up for anything.

Andrew Dalton

Bike Magazine December 2017