Large parts of inner London are 20mph, including most of Hackney, Tower Hamlets and the City. A limit is a maximum, not a target, and the examiner marks both halves of that: creeping over it, and crawling well under it for no reason. In an automatic the first is the harder problem, because the car will accelerate on its own.
If you learn to drive in the E, EC or IG postcodes, a large share of your lesson time will be spent at 20mph. It is the default across much of Hackney and Tower Hamlets, across the City, and on a growing share of the main road network.
Holding it accurately is a skill in its own right, and it is one that automatic drivers have to work at more than manual drivers do.
How Much Of London Is 20
Transport for London reports that 267km of TfL's roads have a 20mph speed limit, and that 20mph has applied throughout the central London Congestion Charging Zone since March 2020. TfL's stated aim is for 20mph to become the default speed limit in central London and all inner London by 2035.
That is only the TfL road network. The larger part of the 20mph mileage in East London is on borough roads, where councils have set 20mph across most or all of their residential streets. In practice, if you are on a street in Hackney or Tower Hamlets that is not a red route, the working assumption is 20 until a sign tells you otherwise.
TfL's case for it is a collision one: "if you hit someone at 30mph they're 5 times more likely to die than if you hit them at 20mph". Whether or not you find that persuasive, it explains why enforcement has tightened rather than relaxed.
A Limit, Not A Target
Rule 124 of the Highway Code sets out the legal position: "You MUST NOT exceed the maximum speed limits for the road and for your vehicle." Rule 125 then adds the part people skip: "The speed limit is the absolute maximum and does not mean it is safe to drive at that speed irrespective of conditions." Both are on gov.uk.
On a narrow Hackney street with cars parked both sides, children on the pavement and a cyclist ahead, 20 may be too fast. On the same street at six on a Sunday morning it is not. The examiner is assessing your reading of that, not your ability to pin the needle at a number.
Why Holding 20 Is Harder In An Automatic
This is the part that is rarely explained, and it is the reason automatic learners lose marks on speed in zones where they know the limit perfectly well.
An automatic gearbox in drive creeps. With your foot off both pedals on a level road, the car will hold a slow walking pace on its own. On any downhill gradient it will accelerate, and it will keep accelerating, because there is no engine braking from a low gear holding it back.
Kings Head Hill in Chingford and the drop off Hollybush Hill are both places where a car left alone gains five miles an hour without the driver doing anything.
Three consequences follow:
- The brake is a speed control, not just a stopping device. In a 20 zone you will use small, brief brake applications to trim speed far more often than a manual driver would, because you have no gear to hold you.
- Coasting is not neutral. Taking your foot off the accelerator in a manual on a hill slows you down. In an automatic it often does not, or does so far more gently than you expect.
- Moving off is where the overshoot happens. Automatics move away briskly, and a normal amount of accelerator gets you to 25 before the end of a short street. The fix is to reach your speed and then come off the accelerator, rather than holding a constant pedal position.
None of this is difficult. It is just different, and nobody tells you. If you are new to an automatic, the mechanics of the selector and what drive actually does are covered in the automatic gear selector explained.
How Examiners Mark Speed
Speed appears on the DVSA's published fault list twice over. "Not driving at a safe and reasonable speed" is tenth on the list of reasons people fail, and it covers both directions.
| What you did | How it tends to be treated |
|---|---|
| Drifted to 23 or 24 briefly, then corrected | Often nothing, or a single driving fault if it happens repeatedly |
| Held 25 to 27 along a 20 street | A driving fault, and a serious one if there were pedestrians or parked cars close by |
| Did 30 in a 20 outside a school at the wrong time | Serious, because the risk is real rather than technical |
| Drove at 12mph on a clear 20 road for no reason | A driving fault for undue hesitancy or being unnecessarily slow, and it holds up traffic behind you |
The last row is the one people do not expect. Driving well below the limit with no hazard to justify it is a fault, and it is a common one among nervous candidates who have decided that slow equals safe. What the examiner wants is a speed that matches the road, which in a clear 20 zone is close to 20.
The wider list of what gets marked, and how the fault count works, is in the top reasons people fail the driving test.
Knowing What The Limit Is
You will not always see the terminal sign. Two clues fill the gap.
Street lighting
Rule 124 states that a limit of 30mph "generally applies to all roads with street lights (excluding motorways) unless signs show otherwise". So lit road with no signs means 30. In inner London that default is increasingly overridden, which is exactly why the second clue matters more here than elsewhere.
Repeater signs
Where a limit differs from the default for that type of road, small repeater signs appear at intervals. In a 20 zone they are frequently on lamp posts rather than at the kerb, and they are easy to miss if your eyes are down.
If you have been driving for a few minutes on a residential street in Hackney and you have not seen a repeater, the safe assumption is still 20, because the borough default is 20 and the sign you missed was probably at the zone entry.
Roundels painted on the carriageway are also common in London and are easier to pick up at low speed than post-mounted signs.
Where It Bites In East London
- Whitechapel Road and the Mile End Road corridor. Wide, straight, and 20. Wide straight roads invite speed, and the width is the trap.
- Mare Street and the Hackney back streets. Parked both sides, cyclists filtering, and a limit that is easy to exceed by simply not braking.
- The City. Short blocks, frequent junctions, and pedestrians who step out because they are used to traffic moving at 20.
- Roman Road and Victoria Park. Market traffic, loading, and school times.
- Boundaries between borough roads and red routes. The limit changes as you join or leave a main road, and that transition is where most genuine mistakes happen.
That last point is worth dwelling on. The moment of risk is not the middle of a 20 zone, where you have settled. It is the first two hundred metres after the limit has changed, in either direction. Coming off the A12 into a residential street, your sense of speed is calibrated to the road you just left, and 25 feels like crawling.
Enforcement, And Why It Has Tightened
TfL states that "The Metropolitan Police enforces speed limits across most of London's roads", and reports that in 2024/25 the Metropolitan Police enforced 779,440 speeding offences, around five times the level of enforcement when Vision Zero launched in 2018. TfL has also recalibrated cameras to enforce 20mph limits where they apply.
For anyone in their first two years after passing, speeding matters more than it does later, because six or more penalty points within two years revokes the licence and sends you back to both tests. The rest of that picture is set out in the complete guide to learning to drive in East London.
What To Practise
Speed control in a 20 zone is a footwork drill, and it is quick to fix. Spend part of a lesson doing nothing but holding 20 along a residential street, with the instructor calling your speed every few seconds so you learn what 20 looks like out of the windscreen rather than on the dial.
Then do the same on a gradient, where the automatic will try to run away from you, and again pulling away from a series of junctions.
If you are close to test and want to know whether your speed is actually costing you marks, that is one of the specific things a mock test answers, because a fault you cannot feel is a fault you cannot fix. The same scanning habit that catches repeater signs also catches the markings covered in box junctions explained.
Holding a steady 20 in an automatic is a footwork problem rather than a knowledge problem, and it takes about twenty minutes of a lesson to fix once someone shows you where your right foot is going wrong.
Book automatic lessonsCommon questions about 20mph limits
Is all of London 20mph now?
No. TfL reports 267km of its own roads at 20mph and 20mph across the central London Congestion Charging Zone since March 2020, with an aim of 20mph as the default in central and inner London by 2035. Much of East London beyond the red routes is already 20 on borough roads, but plenty of main roads remain 30 or higher.
Will I fail my test for going 24 in a 20 zone?
A brief drift that you notice and correct is usually not marked, or is one driving fault if it keeps happening. Holding 25 or more along a street with parked cars and pedestrians is where it moves toward a serious fault, because the risk becomes real rather than technical.
Can I be marked down for driving too slowly?
Yes. Driving well under the limit with nothing to justify it is marked as undue hesitancy or as failing to make normal progress. The examiner wants a speed that fits the road and conditions, which on a clear 20 street is close to 20.
Why does my automatic speed up on its own?
A car in drive creeps at idle and has no low gear holding it back on a descent, so it accelerates downhill with your foot off both pedals. That is normal. The answer is to treat the brake as a trimming control and apply it early and lightly rather than waiting for the speed to build.
How do I know the limit if I missed the sign?
Look for repeater signs, which in 20 zones are often mounted on lamp posts, and for roundels painted on the carriageway. A lit road with no signs is 30 by default under rule 124, but in inner London that default is frequently overridden, so treat residential streets as 20 unless you have positively seen otherwise.
If your speed wanders in 20 zones, that is a specific, fixable thing to spend an hour on rather than something to hope goes away on the day.
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Published 1 September 2026. Prices and DVSA figures are checked when this page is revised. If anything here has changed, ring us and we will confirm it.