There isn’t anything in Law or the Highway Code that explicitly says that cyclists are allowed to filter. So are we?
Looking into a few of the highway code rules in detail we come across a few things that suggest that we can and that other road users should expect two-wheeled vehicles to be filtering.
Rule 88 is in the motorcyclists section, but the advice is sound and shows that motorcyclists are allowed to filter. Note the advice here, do it slowly and take care!
88 - Manoeuvring. You should be aware of what is behind and to the sides before manoeuvring. Look behind you; use mirrors if they are fitted. When in traffic queues look out for pedestrians crossing between vehicles and vehicles emerging from junctions or changing lanes. Position yourself so that drivers in front can see you in their mirrors. Additionally, when filtering in slow-moving traffic, take care and keep your speed low.
Rule 160 shows that you should be looking out for two-wheeled vehicles filtering
160 - Once moving you should
- be aware of other road users, especially cycles and motorcycles who may be filtering through the traffic. These are more difficult to see than larger vehicles and their riders are particularly vulnerable. Give them plenty of room, especially if you are driving a long vehicle or towing a trailer
Rule 211 shows again that you should be looking for two-wheeled vehicles filtering
211 - It is often difficult to see motorcyclists and cyclists, especially when they are coming up from behind, coming out of junctions, at roundabouts, overtaking you or filtering through traffic. Always look out for them before you emerge from a junction; they could be approaching faster than you think. When turning right across a line of slow-moving or stationary traffic, look out for cyclists or motorcyclists on the inside of the traffic you are crossing. Be especially careful when turning, and when changing direction or lane. Be sure to check mirrors and blind spots carefully.
It seems pretty clear from the sections of the highway code that I have listed above that filtering is legal and that motorists should be aware of it and look for vehicles filtering.
Why is there no legislation/law that says it’s legal? Well legislation says what you can’t and what you must do. Not things you are allowed to do but don’t have to do. As such there is no mention of it any legislation regarding road use.
So who is at fault if there is a collision?
You have to look at each case for its own merits and perhaps compare it to previous cases.
Generally there are a few things that make a difference. How you approached the situation, was it slowly and with care?
Was the motorist cautious, did they take their time and indicate clearly before they moved?
Was their warning signals to you that something might happen (stopped vehicle with a gap in front of it for an example).
There is a thread on a motorcycling forum that discusses how to prove your case with an insurance company. It’s a very good read but note that since it was published in 2005, there have been many changes to the highway code, not just wording but also numbering. So make sure you check with the highway code first.