Drivers who undertake other motorists for being too slow on the motorway could be fined £100 - although the practice is commonplace on British roads, people could end up with a hefty fine.
Although there isn't a law specific to undertaking, doing the driving move recklessly could result in a fine for careless driving or driving without due care and attention.
This usually means three points on your driving licence and a £100 fine, although some police forces may offer a driver education course as an alternative.
Rule 268 of The Highway Code states: "In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to you right. Do not weave in and out of lanes to overtake."
What is undertaking and why is it frowned upon?
Undertaking is when you overtake on the inside lane - when you overtake a slower vehicle on the road using a lane that is kerb side to the vehicle you are passing. In the UK this would be a lane to the right of the vehicle being passed.
This happens usually on roads where there is more than one lane in the same direction, such as motorways. Where traffic is congested and everyone is moving at similar speeds you may be able to undertake to keep up with traffic in your lane even though it means you pass vehicles in the lane to your right.
However, you shouldn't weave in and out of the lanes to get ahead. The Code strongly advises that you avoid overtaking generally and you can get into trouble if you decide to move across three lanes.
