Almost every parent knows the child seat rules for their own car. Far fewer know that those rules change when the vehicle is licensed, and the discovery usually arrives at the worst possible moment, on a pavement at five in the morning with a flight to catch. The law here is genuinely different from the one most families operate under day to day, and the difference exists for reasons that make sense once explained but which nobody explains at the point of booking. This guide sets out what actually applies when children travel in a licensed vehicle, why an exemption exists at all, which seat suits which child, and how to arrange a family journey so that nothing has to be improvised at the kerb. It is written for the practical questions parents ask rather than as a summary of regulations, and it covers the things that go wrong: seats that do not fit, luggage that does not fit alongside them, and the assumption that a booking form has captured something it has not.
The general rule, and where it stops
In the United Kingdom, children must normally use a child car seat until they are 12 years old or 135cm tall, whichever comes first. After that a seat belt alone is sufficient. The seat must be suitable for the child's height or weight depending on which standard it is approved under, and it must be correctly fitted. That is the rule most parents know and follow.
Where it becomes more complicated is in licensed vehicles. Taxis and private hire vehicles carry an exemption that does not apply to a private car, which means a child may in some circumstances travel without a child seat where none is available. The exemption is not an invitation. It exists because the alternative, in the days before pre-booking was normal, was a family stranded at a rank at midnight with no lawful way home. It was designed for the unplanned journey, not the one arranged three weeks in advance. Treating a foreseeable family airport transfer as though it were an emergency hail misreads both the intention and the risk.
Why an exemption exists at all
The reasoning is worth understanding, because it tells you when to lean on it and when not to. A licensed vehicle cannot know in advance who will get in. A hackney carriage hailed in the street may carry a toddler on one job and four adults on the next, and no operator can stock every size of seat in every car on the chance it is needed. Faced with that, the choice was between allowing an unrestrained child in an emergency or leaving families with no legal transport at all, and the law chose the former as the lesser harm. That reasoning collapses entirely for a pre-booked journey. When a booking is made in advance, the operator knows exactly who is travelling and can fit the correct seat before the car leaves the depot. The uncertainty the exemption was written to solve simply does not exist. This is why any competent operator will treat a family booking as a seat requirement rather than an exemption opportunity, and why we ask for ages at the point of booking rather than leaving it to chance.
Which seat suits which child
Two approval standards run in parallel, which is the main source of confusion. The newer standard, often called i-Size, categorises seats by the child's height, and requires children to remain rear facing until at least 15 months. The older standard categorises by weight in groups. Both remain legal, and a seat approved under either is acceptable provided it suits the child.
In practice families fall into four broad situations. An infant needs a rear facing carrier, and rear facing is markedly safer for the neck in a frontal impact, which is why the minimum age keeps rising. A toddler moves to a larger seat, often still rear facing well beyond the minimum, since longer is better rather than merely acceptable. A young child then moves to a forward facing seat with a harness or an integrated impact shield. An older child uses a high backed booster, which routes the adult belt across the strong parts of the body and, importantly, protects the head and torso in a side impact in a way a backless cushion does not. If you tell us ages and rough heights, we will fit the right one rather than guessing. One further point is worth knowing: a backless booster cushion is only permitted for larger children under the current rules, and even where it is legal a high backed model is meaningfully safer, so we fit those by default rather than the cushion.
What to tell us, and when
The single most useful thing a parent can do is give the details at the time of booking rather than on the day. Seats cannot be added once a driver has set off, because they are fitted at the depot and a car already on its way to you has whatever it left with. There is no charge for them, so there is no reason to under-declare.
Tell us the number of children, each child's approximate age, and their rough height or weight if you know it. Say whether you are bringing your own seat, which many families prefer and which is entirely welcome. Mention a pushchair explicitly, because a folded pram takes considerably more boot space than people expect and is the most common cause of a luggage problem on a family transfer. And say if two children need seats side by side, because three child seats across a single row is not possible in every vehicle and may point to a larger one. Our family airport transfers are arranged around exactly these details.
Bringing your own seat
Many parents would rather use the seat their child already knows, and there is a good argument for it. A familiar seat is one the child will settle into without protest at an unsociable hour, you know it is correctly adjusted for them, and you know its history, which matters because a seat involved in a previous collision should be replaced even if it looks undamaged. If you are flying, there is a further consideration. A seat you bring to the airport has to go somewhere: either checked into the hold, where it may be handled roughly, or carried through the terminal, which is unwelcome with children and luggage in tow. Many families use ours on the outbound run and their own on the return, or the reverse. Tell us which you intend and we will plan the space accordingly. If you bring your own, allow a few extra minutes at the pickup so the driver can fit it properly rather than hurriedly, since a seat fitted in a rush is a seat fitted badly.
Space is the constraint people forget
Child seats consume space in two directions and families routinely underestimate both. They take a seat position, obviously, but a rear facing seat also pushes the seat in front of it forward, which can make an adult position behind the driver unusable. Three seats across a row is possible in some vehicles and impossible in others, depending on belt positions and width. Meanwhile the luggage grows. A family holiday generates more and bulkier cases than the same number of adults travelling on business, and a folded pushchair takes the space of a large suitcase on its own. Travel cots, car seat bags and buggy boards add further. This is why family transfers so often need a people carrier where the passenger count alone would suggest a saloon. Count seats and luggage separately, add the pushchair as its own item, and let the larger figure choose the vehicle. Our Mercedes V-Class people carrier exists largely for this pattern.
Making a long journey bearable
Beyond the legal minimum there is the question of everyone arriving in a reasonable state, which for a two hour run to a cruise port or an early departure matters as much. Timing helps more than anything else. A journey that overlaps a nap is transformed, and for a very early flight most children will sleep the whole way if they are carried out in what they slept in and changed later. Practical things worth doing: keep one small bag accessible in the cabin rather than in the boot, with drinks, snacks and anything needed for a change, because stopping to open the boot on a motorway is not straightforward. Ask for a comfort stop on any journey over about an hour rather than hoping; drivers expect it and it costs nothing but a few minutes. Sit where you can reach the child rather than where the adults would naturally sit. And do not be embarrassed about mess. Chauffeur cars are valeted between shifts and a driver who works family transfers has seen worse than whatever your toddler is planning.
Airports with children, in the right order
The transfer is only one part of a day that families usually find harder than they expected, and a little sequencing removes most of the friction. On departure, work backwards from the airline's check-in deadline rather than from the flight time, then add a margin for the fact that everything with children takes longer than planned. Ask to be set down at your own terminal's departures entrance rather than a shared drop-off point, which saves a walk with a pushchair and cases. On arrival, the useful thing to know is that the free waiting period runs from the moment the aircraft lands rather than from your booked time, which covers the long, slow shuffle through passport control that families with tired children know well. Your chauffeur is inside the arrivals hall with a name board rather than waiting in a car park, so there is no phone call to make one handed while holding a toddler. If you are landing at Heathrow specifically, the terminal you arrive into determines where the driver stands, which is why we ask for a flight number rather than an airline. We have covered how meeting inside the terminal works in more detail separately.
Safety habits that matter more than the seat
A correctly chosen seat that is incorrectly used offers far less protection than parents assume, and a few habits close most of the gap. The harness should be snug enough that you cannot pinch a horizontal fold of webbing between finger and thumb at the shoulder, which is tighter than most people leave it. Bulky coats should come off before the harness goes on, because a padded coat compresses in a collision and leaves the harness effectively loose; a coat over the top afterwards is fine. The chest clip or harness height should sit at armpit level rather than across the stomach or the neck. For older children in boosters, check the adult belt runs across the collarbone and the hips rather than the neck and the soft abdomen. And keep loose hard objects out of the cabin, since anything unsecured becomes a projectile. None of this takes long once it is habit, and a driver will always give you the moment to do it properly rather than rushing you into the car.
Booking the return leg too
One habit saves families a great deal of trouble: book both directions at the same time. Arranging the outbound run and leaving the return until you are abroad means doing it on poor wifi, in a different time zone, at the end of a holiday when nobody wants to think about logistics. It also means the seats you need may already be committed elsewhere on that date. Booking both together fixes the vehicle, the seats and the price in one conversation, and the return leg is tracked against your inbound flight so a delay on the way home is handled exactly as it would be on the way out.
Do you provide child seats?
Yes, free of charge. Give us the ages when you book so the correct seats are fitted before the car sets off. They cannot be added once your driver is already on the way, because seats are fitted at the depot rather than carried spare in every vehicle.
Is a child seat legally required in a licensed vehicle?
Licensed vehicles carry an exemption that private cars do not, but it was written for unplanned journeys. A pre-booked transfer is entirely foreseeable, so the right approach is to fit the correct seat rather than to rely on the exemption. We treat a family booking as a seat requirement.
Until what age does a child need a car seat?
Until 12 years old or 135cm tall, whichever comes first. After that an adult seat belt is sufficient. Which seat suits before that point depends on height or weight according to the standard the seat is approved under, which is why we ask for ages and rough heights.
Can I bring my own child seat?
Yes, and many families prefer to. A familiar seat is one a child will settle into without protest at an early hour, and you know how it has been used. Allow a few extra minutes at pickup so it can be fitted properly, and tell us in advance so the boot space is planned for.
How many child seats can you fit in one vehicle?
It depends on the vehicle, and three across one row is not always possible. Belt positions and width vary, and a rear facing seat also pushes the seat in front of it forward. Tell us how many children need seats and we will assign a vehicle that genuinely accommodates them.
Does a pushchair fit as well?
Yes, but it must be counted as luggage. A folded pram takes roughly the space of a large suitcase, and travel cots and car seat bags add more. Mention the pushchair explicitly when booking, since it is the most common reason a family booking needs a larger vehicle than the passenger count suggests.
What should we bring in the cabin rather than the boot?
Drinks, snacks, anything needed for a change and one small bag. Opening a boot on a motorway is not straightforward, so anything you may want during the journey should travel with you. Everything else can go in the back.
Can we stop on a long journey?
Yes, just ask the driver. On any run over about an hour a comfort stop is sensible rather than optional with young children, and services on the main routes are directly on the way. It costs nothing beyond the few minutes it takes.
How tight should a harness be?
Tight enough that you cannot pinch a horizontal fold of webbing at the shoulder. That is snugger than most people leave it. Bulky coats should come off first, since padding compresses in a collision and leaves the harness effectively loose, and a coat can go over the top afterwards.
What if my flight is delayed with children on board?
The pickup moves with the aircraft at no extra charge. Your driver tracks the flight and follows the actual landing time, so a delay simply means a later meeting. With children this matters more than usual, because the alternative is standing in an arrivals hall wondering whether the car has given up on you.
