In Hussein's bedroom, near the contract with Lucifuge Rofocale, police found another handwritten letter pledging to "offer some blood" in exchange for making a girl at his school "fall deeply in love with me".

Danyal Hussein had just turned 18 when he launched a ferocious knife attack on strangers Bibaa Henry and Nicole Smallman as the sisters celebrated Ms Henry's 46th birthday last summer. What prompted the teenager to commit such a horrific crime?

Shortly after 01:00 BST on 1 July 2020 armed police smashed the door of an inconspicuous family home in a quiet cul-de-sac in Blackheath, south-east London.

Inside they found a contract that Hussein, now 19, believed he had drawn up with a demon.

In large, childish handwriting, he promised to "perform a minimum of six sacrifices every six months for as long as I am free and physically capable".

The agreement was headed, "for the mighty king Lucifuge Rofocale" who, according to some Satanic cults, is the demon in charge of hell's government and treasury.

In exchange Hussein would win the Mega Millions Super Jackpot and "receive fruitful rewards" including "wealth and power".

At the bottom Hussein had signed his forename in his own blood. There was a space - left unsigned - for the demon to leave his mark.