Awain specialises in creating jewel-encrusted keys for the world's most expensive vehicles, and the Phantom is its ultimate creation at a price of €500,000 (approx. £430,000 at the current exchange rate). That figure is not a typo, either. This is a key that costs more than a Lamborghini Aventador SVJ with a base price of £291,667.

Gallery: Awain Custom Key

Almost half a million pounds buys you a key with a total weight of 34.5 carats of tiny diamonds around the outside. Precious stones also line the face. The rest of the fob contains 175 grams of solid 18-carat gold. Buyers can customise the look by choosing the materials for the centre section, including multiple colours of leather or wood. The company is making just a single Phantom to ensure that that creation remains unique.

If you'd prefer something a little more modest, Awain makes some less expensive keys, although they still aren't really affordable. The Serenity is 80,000 euros (£69,000), and it features a mix of 20 carats of diamonds and 175 grams of gold. The Quantum costs 49,000 euros (£42,000) for a combination of 3.6 carats of diamonds and 175 grams of gold. These offerings are limited to 20 examples each.

Awain makes custom keys for models from Bugatti, Bentley, Aston Martin, Maserati, Lamborghini, McLaren, Maybach, Rolls-Royce, Porsche, and Mercedes-Benz, which makes its product even weird. Most of these model have key-less access, meaning that owners never need to take the key out of their pocket. So no one would ever see this £430,000 piece of jewellery.