From Royal Mail's guidance when sending alkaline batteries internationally:
Must be new and sent unopened in their original retail packaging. Surround with sufficient cushioning material to protect each item from damage. Wrap each item, including plugs, individually. Place item in a rigid container and cushion to avoid movement. Any equipment sent with batteries or cells must be secured against movement within the outer packaging and must be packed to prevent accidental activation. The sender’s name and return address must be clearly visible on the outer packaging.
For something like a light brick, I wouldn't worry about it too much. I've sent a few such items abroad without any trouble. Of course I always mark the customs form "plastic toy parts" so as not to raise any red flags.
The guidance for sending alkaline batteries internationally from the UK seems pretty clear. Alkaline batteries should not be sent unless they're in their retail packaging, which in the case of Lego would be the retail box, or at least the cellophane bag
"Alkaline, nickel metal hydride (NiMH) and nickel cadmium (NiCd) batteries may only be sent when new and in their original packaging."
"Electronic items sent with new alkaline, nickel metal hydride (NiMH) or nickel cadmium (NiCd) batteries: Must be new and sent unopened in their original retail packaging."
Comments
As long as it's low quantity, it's OK I think.
From Royal Mail's guidance when sending alkaline batteries internationally:
Must be new and sent unopened in their original retail packaging. Surround with sufficient cushioning material to protect each item from damage. Wrap each item, including plugs, individually. Place item in a rigid container and cushion to avoid movement. Any equipment sent with batteries or cells must be secured against movement within the outer packaging and must be packed to prevent accidental activation. The sender’s name and return address must be clearly visible on the outer packaging.
Brian
That's what I thought Lawrence.
Katie
"Alkaline, nickel metal hydride (NiMH) and nickel cadmium (NiCd) batteries may only be sent when new and in their original packaging."
"Electronic items sent with new alkaline, nickel metal hydride (NiMH) or nickel cadmium (NiCd) batteries: Must be new and sent unopened in their original retail packaging."
http://www.postoffice.co.uk/prohibited-goods-international#prohibited
If it were me I'd send it anyways; the chances of even a customs inspection realising that there's a battery in there is probably very slim.