Here is our definitive guide:
A black or grey matt morning coat, single-breasted with peaked lapels, curved front edges sloping back into tails worn with grey or grey and black striped trousers.
Waistcoats are usually dove grey, buff, yellow or duck-egg blue and either double or single-breasted.
Double-breasted waistcoats must be worn fully buttoned whereas the single-breasted should be worn with the bottom button left undone.
A white or light-coloured shirt with a white turned-down collar, double-cuffs and cufflinks should be accompanied by a conventional neck-tie, cravats or bow-ties are not permitted.
A black or grey top hat must be worn whilst in the Royal Enclosure and may be removed whilst in restaurants and private boxes.
Black lace up shoes should be worn; either an oxford or a brogue, with black socks.