Cartier

Cartier was founded in Paris in 1847 and is owned by Richemont. Its London flagship at 175-177 New Bond Street has been Cartier's since 1909. It reopened in 2018 after a full redesign, with engagement and bridal on the ground floor. There's a second boutique at 40-41 Old Bond Street, plus concessions in Harrods and Selfridges.

Unlike most houses in this tier, the flagship works as a walk-in shop with long hours, including Sundays. You can book, but you don't have to.

The engagement range is built on house designs, led by the Solitaire 1895 and Destinée. Cartier's "Set For You" service lets you choose a design and have a stone set to order. That's customisation within Cartier's designs, not bespoke from scratch.

Cartier UK lists smaller diamond rings such as the Étincelle de Cartier from about £2,500. Solitaire prices depend on the stone and are given in the boutique. Natural diamonds only for centre stones — Cartier has publicly come out against lab-grown.

Our view: with Cartier, the design is the point. The Solitaire 1895 is recognisable, and that recognition is part of what you're buying. If you love the design, buy it here. If you mostly want a round solitaire, any good Hatton Garden workshop can make a classic four-claw setting with a GIA-certified stone of the same grade, and you'll see exactly where the money goes.