The maximum size for items of hand luggage is 56cm x 45cm x 25cm per bag. However, airlines apply their own operational policies governing the number of items of hand baggage which may be taken in to the aircraft cabin. Flights to Banjul and Dakar are currently adhering to the one piece of hand luggage rule.
Where possible, put all liquid items in your hold baggage. This includes water and other drinks, creams, sprays, pastes and gels.
Liquids, gels and aerosols are only allowed in individual containers of 100ml. All containers must fit comfortably in one, transparent, re-sealable bag no larger than 20cm x 20cm (e.g. a freezer bag).
Requirements can vary slightly depending on the airport.
Please note that the same rules on liquid items apply at Brussels Airport, therefore you will not be able to take any liquid items (including duty-free) bought at a UK airport. There is a good selection of shops at Brussels Airport though for buying your duty-frees.