Does thickness of BD cases differ between US and UK?

[Bruce Morrison]

I'm in the UK but, like many other BD users, I've imported a US player and buy US BDs. However, an on-line retailer mistakenly sent me a UK BD yesterday. It's been returned for a refund, but what surprised me was that the disc case was significantly thicker than the standard US cases. Is this true generally? I hadn't realised that there was any difference in the cases used in the two markets, but it seems to be one more good reason for using US BDs, as the saving in shelf space will be considerable as my BD collection grows.