Was just watching the greater rod race, where Matt and Brownie were in Ireland on Lough Sheelin.
Having stopped for a brew up and bite to eat, that muppet Brownie was fuelling the Kelly but had the cork in it,

a big NO NO.
Its written on them not to boil them with the cork in!!! reason? The steam makes the cork swell, thus causing an air tight seal that builds pressure!!
Result--- Bang@@

at best just the cork flies out with boiling water and steam spilling everywhere!!!! At worst very serious burns and split Kelly.
The lads down at Conn dont put the warning there just for the sake of it, and if used as they should! no angler should be without them, My workmen have nicked one of mine to use on the farms when we are erecting sheds, they say it beats a flask hands down for a good hot cup of tea, soup, coffee or Oxo, I reckon they just want a bit longer crib break.
Happy fishing
Mike