We've been travelling for years, and yet most of us still can't remember how much liquid we're allowed to take on planes when frantically packing the night before.

So, with holiday season edging ever closer, and COVID-19 no longer a global health emergency, maybe this is the year to finally get clued up before hitting the airport.

Ready for a smooth-sailing summer, here are all the answers you need on stuffing those liquids into your hand luggage.

What counts as liquid on a plane?

To save yourself the embarrassment of holding up the queue and getting your bag searched at security, pack appropriately.

As there are restrictions on the amount of liquids you can take on board your flight in your hand language, it's best to pack most of it safely away in your hold luggage, which you'll check in.

To save you wondering what is and isn't classified as a liquid, here's what is, as per gov.uk guidance:

• all drinks, including water

• liquid or semi-liquid foods, for example soup, jam, honey and syrups

• cosmetics and toiletries, including creams, lotions, oils, perfumes, mascara and lip gloss

• sprays, including shaving foam, hairspray and spray deodorants

• pastes, including toothpaste

• gels, including hair and shower gel

• contact lens solution

• any other solutions and items of similar consistency

How much liquid can you take on a plane?

But, for those of you who are going on a long haul flight, or who like to travel with a few essentials, these are the rules for taking liquid through security:

• containers must hold no more than 100ml

• containers must be in a single, transparent, resealable plastic bag, which holds no more than a litre and measures approximately 20cm x 20cm

• contents must fit comfortably inside the bag so it can be sealed

• the bag must not be knotted or tied at the top

• you’re limited to one plastic bag per person

• you must show the bag at the airport security point

While it might be better to bring your own resealable plastic bag, don't fret if you forget it, as they should also be outside security at the airport for you to help yourself to.

And don't be deceived into thinking that you can take containers larger than 100ml if they're only partly full. For some reason, you can't. But there are some exceptions for more more crucial purposes.

You can take liquid containers larger than 100ml on a plane if they are for essential medical purposes, are for special dietary requirements or contain baby food or baby milk.

You can also take liquids that you bought at an airport or on the plane itself through security if the items are sealed inside a security bag on purchase, and the receipt is sealed in the security bag and visible.

Gov.uk also states that you shouldn't open the security bag until you reach your final destination. You should also be aware that airport staff might need to open your items to screen the liquid at security.

You can only carry one lighter on board, which should be put inside a resealable plastic bag and kept on you throughout the flight. You can't put it in your hold luggage, or put it in your hand luggage after screening.

Are the rules changing?

While these types of regulations have been standard since 2006 after a foiled terrorist plot, in 2019 Boris Johnson said the rules would be eased at major UK airports by 1 December 2022, though this deadline was of course missed.

But in April this year, London City Airport became the first major UK airport to abandon the 100ml liquid rule, allowing passengers to carry up to two litres in their hand luggage. The need to remove items like laptops from their luggage was also dropped.

The rules around taking liquids and large electrical items through security are now set to change by 2024, thanks to the installation of new technology at major airports across the UK – as promised by the latest government deadline.

"By 2024, major airports across the UK will have the latest security tech installed, reducing queuing times, improving the passenger experience, and most importantly detecting potential threats," Transport Secretary Mark Harper said in December.

"Of course, this won’t happen straight away – this is going to take 2 years to be fully implemented. Until then, passengers must continue following the existing rules and check before travelling."

For more information on what else you can take on a plane, see the gov.uk's full guide on hand luggage restrictions at UK airports.