My late lamented father-in-law was an engineer. Many years ago (early 70s, I guess) he designed a large piece of machinery and, to avoid unnecessary expense and work, had a model made first. On the day it was due to be delivered, there was a message that his model had arrived. "Splendid", he said, "bring it up to my office."

"Er, that's a bit difficult, Mr Cope. It's on a low loader." came the reply.

The workshop had missed the bit at the top that said 'all dimensions in millimetres' and made it in inches!

Steve