He called himself the ‘Eunuch Maker’ - and took twisted pleasure in performing gruesome surgical procedures in his basement flat, including sawing off men’s penises and testicles with a kitchen knife and severing entire limbs.

Marius Gustavson turned a room under the stairs of his rented two-bedroomed flat, in a pleasant row of Victorian terraces in north London, into a dungeon of horrors - broadcasting his butchery live to 20,000 paying subscribers on the internet.