Yes, you usually can — but the answer depends on which three wires those actually are, and that is worth ten minutes of checking before you buy anything, because "neutral" in a 1970s switch box is frequently not what people assume it is.
What a smart switch needs that a normal one does not
A plain mechanical switch just breaks a circuit. It does not care about anything else.
A smart switch is a small computer that has to stay powered even when the light is off, so it wants permanent live and neutral at the box, plus the switched live going out to the lamp. That is one more conductor than the old switch needed, and in older houses that conductor is often simply not there.
Why older boxes often have no neutral at all
The usual layout is called a switch loop. The cable runs up to the ceiling rose, and in the switch box you have only two cores: one permanent live, one switched return going back up to the fitting. Both are live in different states. Neither is a neutral.
If that is what you have, no amount of careful wiring will make a neutral-requiring switch work, because there is no return path at that box. It is not a skill problem — the wire does not exist.
The more dangerous version
The other thing old boxes do is contain neutrals that belong to a different circuit.
You open the box, see two cables, find a white or grey conductor and reasonably conclude it is your neutral. It may instead be the neutral of a ring main passing through, or of a socket on another breaker.
Connecting your switch's neutral to a neutral from another circuit is the kind of thing that appears to work, then trips the RCD the moment someone switches something else on. In the worst case it leaves current flowing on a conductor you believed was dead. It is also a code violation in most places.
Two checks, in this order
With the breaker off and everything confirmed dead, count the cables entering the box and see where they go. One cable almost certainly means a switch loop and no neutral available there. Two or more means there may be one.
Then confirm rather than assume: with the breaker on, measure between your candidate neutral and the permanent live. You should read your mains voltage. Be careful doing this — and if any part of it is unclear, this is exactly the point where an electrician costs less than a mistake.
If you have no neutral, you still have three options
Option one: a no-neutral switch
These draw standby current through the lamp instead of through a neutral. Modern ones do it well, and many are designed so no capacitor needs fitting at the fitting.
That detail matters more than it sounds. Older no-neutral designs leaked enough current to make LED lamps glow faintly or flicker while switched off, and the usual fix was wiring a capacitor across the lamp terminals up in the ceiling void — which nobody wants to do. If your lamps are LED and low wattage, check the minimum load the switch states and pick one rated for very low loads.
Option two: move the intelligence to the ceiling
A small relay or switch module installed at the ceiling rose, where permanent live, neutral and switched live all actually meet, solves the problem completely. The existing wall switch stays as it is, or becomes just a trigger.
This is usually the cleanest answer for old wiring, and it is what I would do if reaching the fitting is easier than fishing a new cable down the wall.
Option three: smart bulbs
Least work of all, no wiring whatsoever. The catch is that a switched-off switch removes power from the bulbs entirely, so you end up either leaving the physical switch permanently on or fitting a remote that covers it.
One practical note about old cable
1970s insulation is brittle. The copper inside is usually fine, but the sheathing can crack when you fold it back into a box that is already tight — and a smart switch takes noticeably more room than the one you are replacing.
Box extenders exist precisely for this and are worth having on hand before you start, not after.
The honest trade-off
You are choosing between replacing wiring you cannot easily access, or buying hardware that works with what you have. Neither is wrong, but it should be a decision you make deliberately.
Check whether you have a verified neutral first. Everything else — which switch, which method, how much work — follows directly from that one answer.
I work on the manufacturing side, so I have a bias here: I would rather you not buy a switch that needs something your house does not have. If you are comparing models, the specification that actually matters is whether it needs a neutral and, if not, what minimum load it requires: https://xingliaoshop.com/product-category/smart-switch/
Xingliao Smart Home builds smart switches, video doorbells and security cameras on Tuya WiFi and Tuya ZigBee, and runs OEM/ODM programmes from Shenzhen. Factory and ODM capability.
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