Haha, I've done that too; 10L of bio..in a rucksack...on the tube.
My, how it leaked!
People have gotten shot down dead on the tube for less than that!
Only if you are of a South American or Middle Eastern disposition!
Its not open season for middle class civil servants yet (Don't worry its not for lack of trying on Cameron's part!) so Andy should be ok! hahaha
Yes ours we transported in a rucksack but also wrapped in a plastic bag to contain leaks

No danger for me, I'm clearly not middle eastern, in fact in Budapest one of the locals mistook me for an Australian.