By the 1930s, the first handful of mansions on the street were already known as "Millionaires Row."

Hollywood star Gracie Fields and sugar magnate William Lyle were amongst its early residents. After World War II, the overthrown king of Greece, Constantine II (Prince William's godfather) bought property there.

Homes, bought at exorbitant prices, stand completely empty.

The road quickly gained a reputation for excess. Iranian royals fleeing the fall of the Shah have lived there. The Sultan of Brunei owned a house. Saudi Arabian princes, swollen with oil riches, followed. Elton John once sang about the place.

Today, 60% of the homes on the street are owned by hard-to-scrutinize shell corporations registered in foreign tax havens like the Bahamas, Panama, and the British Virgin Islands, research by Insider has found.

The homes are magnets for those keen to stash large amounts of money where it might produce a reasonable return, while avoiding scrutiny.

The result is a bizarre situation that can be observed while walking down The Bishops Avenue. The city's poshest neighbourhood is also sometimes its shabbiest. It's a street where many homes, bought at exorbitant prices, stand completely empty, and in some cases are falling apart.

The Towers, the street's largest single property, has been uninhabited for years, save for passing groups of squatters. Wildlife freely enters through its empty window frames and crumbling masonry.

Counter-intuitive though it may seem, a crumbling house like this is no problem for the owners who invest in it. The real value, experts told Insider, is tied up in the land rather than the buildings on it.

“It feels deeply unfair when people don't pay their taxes.” Robert Palmer, Tax Justice UK

Unlike regular buyers of houses, owners of the shell corporations which own most of The Bishops Avenue have likely bought and sold without having to pay heavy taxes to the UK government.