In short Mirror, signal, manoeuvre (MSM) is the routine before you turn, change lanes, move off, slow down or stop. Check the mirrors to see what is behind and beside you, signal if it would help or warn anyone, then make the manoeuvre in three steps: position, speed and look (PSL). The test marks the mirror check and whether you act on what you saw, not just the glance.
Updated 9 November 2026 · Source: GOV.UK car driving test guidance, checked 9 November 2026
The routine
- Mirrors. Interior mirror, then the door mirror on the side you are moving to. Before moving off or changing lanes, add a blind spot check over your shoulder.
- Signal. Signal if it would help or warn anyone, in good time, and make sure it cannot be misread (for example, signalling left just before a side road you are not turning into).
- Manoeuvre, in three parts:
- Position: move to the right place on the road for the turn or lane.
- Speed: slow down to the right speed, and select the right gear.
- Look: look into the new road or lane early, and decide whether to go or wait.
Practise the routine at the junctions around your test centre with the Driving Test Routes app
When to use it
- Turning left or right at a junction or into a driveway
- Approaching a roundabout and changing lanes on it
- Moving off from the side of the road
- Pulling over to stop
- Slowing down for a hazard
- Overtaking or passing parked cars
The mirror faults examiners mark
- Signalling before checking the mirrors.
- Checking the mirrors too late, or not at all, before slowing down or turning.
- Checking but not acting on what you saw (a cyclist on your left before a left turn, for example).
- Missing the blind spot when moving off or changing lanes.
Mirrors before a change of direction is among the faults that most often lead to a serious fault on the test. See how faults are marked.
Frequently asked questions
What does MSM stand for?
Mirror, signal, manoeuvre. The manoeuvre part is often broken down into position, speed, look (PSL).
Do I always have to signal?
Signal when it would help or warn another road user, including pedestrians. Signalling when nobody is there is not a fault, but a misleading signal is.
Which mirrors should I check?
The interior mirror and the door mirror on the side you are moving to. Before moving off or changing lanes, also check the blind spot over your shoulder.
Read next
Practise on the roads around your test centre
The Driving Test Routes app turns your phone into a practice coach for the practical test.
- Practice routes around UK test centres, with voice directions
- Mock tests that score the drive and list the faults to work on
- All 21 show me tell me questions, with photos of each control
- An emergency stop drill that times your reaction