What max size horse would go in a 7ft headroom lorry?

[Perissa]

What is the maximum size horse you would put in a lorry with 7ft internal headroom?

 

[Mardy Mare]

If my mare is anything to go by, 15.2! She is only 16hh but her ears touch the ceiling and i'm having to sell my new trailer to get a 510 size one as its too small for her.

 

[foraday]

15.2hh!

DEFRA have the internal measurements for head room for horses on their site.

We have 10 foot headroom in ours and our 17hh has enough room