How big can a horse get?

A work colleague asked a question about SQL queries, so I dug out an old post here about that. Problem solved.

But as one problem goes away, another pops up. I used some made up data in that post about animals, and asked:

Can a horse weigh a tonne? No idea.

As Me-From-Years-Ago had been so helpful, I thought Me-from-Today should return the favour. It seems the answer is yes, a horse can indeed weigh that much, and the largest on record is a tonne and a half. At least, according to Wikipedia.