If you want to save money on meals in the departure lounge, you could take your own food in your hand luggage, but be careful what you bring

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Even if you've grabbed a budget deal to fly away, the cost of holidays can rack up from the moment you leave your front door. Once you're through to the departure gates, airport restaurants and cafes can add up as extra expenses before you've got away.

With Birmingham Airport advising customers to "get to the airport as early as you can" so they can clear check-in and security, passengers may end up in the departure lounge for a couple of hours before their flight departs. And then there's the chance your flight may be delayed.

But there is a way to save money, you can bring your own food through security at Birmingham Airport if you play to the rules. Essentially, if it's something solid, like a sandwich you can put it in your hand luggage and put it through the scanner. But if it's liquid-based, like soup, then you can't.

Read more:The latest rules for travelling to France

Be warned though, if you absolutely need to clear security quickly, you might want to think twice about packing food in your hand luggage. You may also want to make sure you eat it before you land abroad, as post-Brexit rules mean you can't bring some fresh items into the EU from the UK.

Food is allowed in your hand luggage, Birmingham Airport says but it must not be in a liquid form (although there are exceptions for baby food). Birmingham Airport's rules are clear in stating passengers are "permitted" to bring food in their hand luggage, but warn that those who do may be held up a bit longer at security.

Birmingham Airport says: "Foods or powders should be packed into hold baggage where possible. Although these items are permitted in hand luggage, they can obstruct images on the x-ray machine, or may be mistaken for suspicious items, so putting them in the hold will help reduce the need for additional checks."

However, Birmingham Airport's rules state that "liquids, pastes and gels" can not be taken through airport security, unless they are placed in 100ml containers. That includes foods that are "liquid" or "semi-liquid".

GOV.UK elaborates on the food passengers can't put in their hand luggage. "liquid or semi-liquid foods, for example soup, jam, honey and syrups" are banned, unless you bring them in clear plastic containers with no more than 100ml in.

The same rules apply to drinks as you can't bring them through in your hand luggage. Any liquids must be placed in 100ml bottles, which must be stored in a clear plastic bag and placed on the security tray. Passengers can take empty water bottles through and fill them in the departure lounge fountains, Birmingham Airport says.

Again, GOV.UK warns passengers that they may be held up if they bring food through security: "Food items and powders in your hand luggage can obstruct images on x-ray machines. Your bags may need to be checked again manually by security. You can put these items in your hold luggage to minimise delays."

If you do take food in your hold luggage, read up on what you can take to your destination country. The EU, for example, bans passengers from taking meat or dairy products from Britain into EU countries.

Airport security can confiscate anything they consider dangerous, even if the items are not banned. "Airport security staff will not let anything through that they consider dangerous - even if it’s normally allowed in hand luggage," says GOV.UK

Yes, passengers can bring baby food through Birmingham Airport security. That includes liquid-based baby food.

Birmingham Airport says: "Essential prescription medicines and baby food and milk/juice are allowed (so long as they are in a teated bottle); just take as much as you’ll need for the flight. Have a doctor’s note or prescription advice for your medicine."

GOV.UK elaborates: "When travelling with a baby you’re allowed to take enough baby food, baby milk and sterilised water for the journey. There is no legal limit to how much you can take however check with your airport before you travel.

"You can carry breast milk in hand luggage even if you’re not travelling with a baby. You cannot carry frozen breast milk in hand luggage.

"Individual containers of breast milk must hold no more than 2,000ml. Each container will need to be screened at the security point. Airport staff might need to open the containers to screen the liquids."

If you do bring your own food through airport security and onto the plane, you may want to eat it or dispose of it before you arrive in your destination country. You may also want to think twice about storing food in your hold luggage

Brexit brought a rule change for those travelling from Britain to the EU. "If you travel to the EU from a non-EU country, you are not allowed to bring any meat or dairy products with you," says the European Union.

You can bring up to 2kg of fruit, vegetables or non-meat/dairy products in your hold luggage, under the EU rules.