Although hat wearing in the population at large is at its lowest level since the reviled toque and tricorne tax of the 1730s, many pensioners still keep a small selection of millinery for those occasions when it is appropriately de rigeur.

According to Glengarry’s definitive guide Formal and Informal Hatiquette (first published by Kelly & Capote in 1886), the following are the optimum choices of headwear for specific situations.

Stovepipe. Funerals, trips on open top buses, attending fancy dress parties as a pencil sharpener.

Fascinator. Weddings, papal conclaves, category A prison visits.

Tam O’Shanter. Burns night, synchronised swimming, smuggling small rodents.

Sombrero. Flamenco dancing, discus throwing, creative pollarding.

Fedora. Mafia charity auctions, picking olives, attending fancy dress parties as a Swiss tennis player.

There are no known situations where wearing a poke-bonnet, Dolly Varden or snood is deemed appropriate.