This fabulous condition coat by high end quality UK brand Dereta we estimate at c 1967 as it was the year the midi first came in to fashion.
The coats were first because that avoided the mini v midi debate that would tear fashion apart for 4 years; you could wear the coat with a mini underneath.
The cut is Regency ie semi fitted but starts to flare from above the waist for that regency frock coat swagger when open with long boots, and the substantial
black velvet collar also evocative of the style, favoured by the later Mod/psychadelic fashionistas. Though this would likely have been worn by a smart 
Mayfair lady about town or at the races, who wanted a nod to that latest look but with chic & class, and equestrianism. A coat for the town and country girl
still in excellent condition. Beautiful heavy gold coloured brass buttons and such a cute half belt at the back, if you like your classic tight leg flat thigh boots this is the coat to go with!
a treat to walk in when open for that swagger. 
It is a lovely red toward the pinker end but def red.
A UK size 10-12