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Is it illegal to undertake other cyclists?

2 November 2010
by blondwig

Last Thursday night I had a bit of a wobble.

Coming off the silicon roundabout in the left-hand lane, right next to the pavement, another cyclist rode up between me and the pavement.

There wasn’t nearly enough room. His jacket caught my handlebars, and we rode along in unison for what felt like far too much time, him coolly silent, me shouting a theme-park-ride “whooooaaah”. Eventually I swerved out towards the middle of the road to get free, and he zoomed quietly off.

Recently people have been undertaking me more and more. Normally I ride quite far out in the middle of the lane – it increases my visibility, and often physically stops cars from pulling hair’s-breadth overtaking manoeuvres. When I’m there I’m not too worried if other cyclists choose to run the car-door gauntlet on the inside.

But on this occasion I decided I’d had enough – I would take a stand and shout something imposing and aggressive to make the point that undertaking is bad.

Now I normally think of this as a good thing, but aggression is not one of my strong points. So I steeled myself, strapped on the fellas and gathered up my best “what the — was that?!

What actually came out was the plaintive tone of a saddened hippy – I may as well have said “not on my rug, man”. Evidently not intimidated in any way, the other guy shouted a merry “sorry!” and rode on.

I thought I’d check whether he’d actually done anything wrong.

Undertaking and the law

There’s no law expressly preventing you from undertaking another cyclist.

Looking at the Highway Code, though, there is some relevant stuff – it says:

  • You should only overtake on the left (i.e. undertake) if the vehicle in front of you is turning right, and there’s room for you to do so (rule 163)
  • But you can pass on the left if you’re in slow-moving traffic in a queue, and you’re moving faster than traffic on your right (also rule 163)
  • Cyclists are allowed to ride two abreast (but no more), except when on narrow or busy roads and when riding around bends (rule 66)

So it looks like the other guy broke the Highway Code – he overtook on the left, I wasn’t turning right, and we weren’t in a queue or slow-moving traffic. It wasn’t even a situation where we could ride two abreast, because we were going around a bend.

If I’d fallen off and sued, I could rely on his failure to follow the Highway Code as helping establish that he was negligent. This would make it easier for me to recover damages for any personal injury or damage to my bike. (RTA s. 38(7))

Although it wouldn’t necessarily be enough on its own to make him liable. He might also point out that I maybe didn’t comply fully with the rules of red lights in going across the roundabout, and may have taken my preferred “racing line” approach to lane changes – so it was perhaps partly my fault too.

I suppose there’s also a chance he could have been prosecuted for careless cycling. In this context, the prosecutor could rely on his breach of the Highway Code as tending to show that he fell below the necessary degree of care. But it might not be enough on its own to secure a conviction – I might need to point to other factors suggesting his cycling was careless, for example the fact that the road was very busy, so there was a risk of forcing me out into other traffic (see my earlier post). (RTA s. 38(7); Jarvis v Fuller [1974] RTR 160, 163)

Like I’ve said before, as a general rule a prosecution would probably only happen if someone was hurt – but there’s got to be a reasonable chance of knocking somebody off if you undertake close by (and I did nearly fall off as a result). 

So is it just me, or have you been ‘undertaken’ too? Would you undertake another cyclist?


Photo by johnmcga from here

11 Comments leave one →
  1. 2 November 2010 11:23

    Great article! Very funny!

  2. Tim permalink
    2 November 2010 12:52

    Far too many people undertaking, imo: it’s just madness because it endangers me, and the idiot who’s doing it …

    Great post as usual – thanks!

  3. 2 November 2010 13:09

    Thanks Tim (and LJ) – v kind

  4. 3 November 2010 14:55

    Another great blog – thanks. Would be interested to know if police ever actually prosecute for undertaking in a car. I can imagine they probably just give the driver a talking to.

    In my own blog at , I’ve posed a question: do you have to have a bell? I always use a whistle instead, but am never sure if that’s entirely legal. Maybe that could be a future blog post for you?

    • 3 November 2010 15:39

      hi els76uk

      thanks for the comment and link to your blog – interesting stuff.

      re undertaking, i’m aware of at least one case where a motorist was prosecuted just for undertaking (when no-one was hurt), but it was at high speed on a motorway. don’t know any more than that.

      re bells, i seem to remember that you can’t sell a new bike without a bell, but you can ride without one (but I haven’t looked into this fully). i’ll bear it in mind for a future post!

  5. Jonny permalink
    4 April 2011 16:40

    First of all, I totally agree that undertaking is not a good idea, and can be dangerous for both cyclists involved.

    However, I frequently encounter cyclists riding quite far out in the bus lane on my cycle to work in London. If I want to over-take them on the outside I have to go almost into the main traffic to get round them. I see this as more dangerous than undertaking if there is regular traffic passing, so in these cases (after riding behind the other cyclist and seeing that they’re not just avoiding drains or daydreaming) I have been known to pass on the inside. Last time I did this I got a lecture on ‘road positioning’ and nearly lamped the guy – does anyone else think it’s a good idea to ride in the middle of the bus lane (rather than to the left), and if so, why?

    • 20 April 2011 17:20

      Along The Vale/Uxbridge Road on the way into London before Shepherds Bush, the bus lane actually has two exceedingly bumpy ‘strips’, meaning that you’re limited to only 2 or 3 possibly road positions; either in the gutter, in the middle of the lane, or on the outer edge. I tend to take the middle, or the outer for overtaking. I’ll also ride in the middle of the bus lane if there’s not an awful lot of traffic around, just to keep clear of potholes/drains/broken glass etc.

      Generally though, I’m moving faster than a fair proportion of the other cyclists I come across, so I’m aiming to overtake rather than undertake.

  6. Robert Gormley permalink
    6 July 2011 11:58

    I’ve been undertaken whilst in the “primary” road position and about to turn left. The roadie looked awfully surprised as I nearly clouted him with my left signal…

    Since then I’ve taken to looking over my left shoulder when turning left rather than using the right shoulder look for all manoeuvres!

  7. Watts permalink
    6 June 2012 23:08

    I’m a huge fan of undertaking.

    Why? Because in London so many cyclists are now riding in the middle of the lane so as ‘cars see them’ and (I quote one cyclist) to “prevent being overtaken too fast and too close.” But what about a cyclist trying to overtake a slow middle lane riding cyclist?

    I encourage as the highway code permits to [in London rush hours] “pass on the left if you’re in slow-moving traffic in a queue, and you’re moving faster than traffic on your right”. That’s most of the time for Londoners.

    HEALTH WARNING: Undertaking is incredibly dangerous to do so with cars especially lorries but to under a cyclist read on because it gets better…

    According to the Highway code “taking the lane” or more erotically “primary position” is only permitted when “passing parked cars whose doors may suddenly open.” It may also be warranted when “preventing traffic overtaking dangerously in narrow roads” and finally “manoeuvring or turning.”

    Riding in the middle of a lane in primary position is therefore not acceptable if you’re on a wide road, heading straight ahead and where no parked cars are present. Cyclists who undertake another cyclist are welcome to do so therefore if the other middle lane primary position cyclist is slow and part of a forming queue that is as much to say you behind them.

    Source of quote:

  8. Andy permalink
    11 January 2013 23:51

    Quoting your text: “But you can pass on the left if you’re in slow-moving traffic in a queue, and you’re moving faster than traffic on your right”

    You have distorted rule 163 in a way that now implies cyclists can undertake slow moving or stationary traffic. Rule 163 says:

    “stay in your lane if traffic is moving slowly in queues. If the queue on your right is moving more slowly than you are, you may pass on the left”

    Pay attention in “”stay in your lane”. Squeezing between the curb and the cars does not create a new lane.

    • blondwig permalink*
      18 January 2013 09:45

      Hi Andy

      In my view it’s open to interpretation. Cyclists will generally be on the left side of the traffic, so slow moving cars may be on the right; this sometimes creates something akin to a ‘two queues in one lane’ situation. In those kind of circumstances, I think there’s an argument that cyclists can pass on the left and still comply with the rule (they would still be staying in their lane). Bear in mind that the rule isn’t all phrased strictly in terms of lanes: it doesn’t say “if the queue in a lane on your right is moving more slowly than you are, you may pass in a lane on the left”.

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