I found this:
From the 22nd September 2006, the UK Department for Transport has restored to normal the hand baggage size restrictions. Each passenger is permitted to carry ONE item of hand baggage up to 10kg with maximum dimensions of 55cm x 40cm x 20cm. These dimensions include the wheels, handles, side pockets, etc.
However, please note that some restrictions on the carriage of liquids in hand baggage remains.
Customers may NOT carry the following items through security in their cabin bag.
Liquid cosmetics, all toiletries, all liquids, all drinks, cigarette lighters, gels, pastes, lotions, (e.g. toothpaste, hair gel, drinks, deodorant, shaving foam, aerosols, etc.)
Cabin baggage CAN contain the following:
Solid cosmetics endash eye shadow, face powder
Electronic equipment, including laptops, phones, portable music and DVD players.
Prescribed medicines in liquid or tablet form e.g. diabetic medicines
Baby milk and liquid baby food (the contents of each bottle MUST be tasted by the parent)
All electronic equipment will need to be removed from the item of hand baggage and screened separately.
Pushchairs and walking aids will be permitted but must be x-ray screened and searched.