Last time I travelled from the UK I was allowed to take empty bottles with me, but there's no "of course" about it. For example you can take a full 50ml bottle,

Last time I travelled from the UK I was allowed to take empty bottles with me, but there's no "of course" about it. For example you can take a full 50ml bottle, but not a 500ml bottle with 50ml of water in it. It's best just to check in advance.