"Kate went off Sadie when she split from Jude. She'd sleep with people if they were important," said a source close to the actress.
"Sadie is in love with Kate, she is possessive over her but Kate is not so interested in her now. I was told that Sadie went mad when she heard Kate was trying to get off with Davinia."
Rebecca White knows only too well the mayhem drugs cause in the supermodel's sex life. "When she's doing cocaine, it's normal behaviour for her to jump on a couch with another woman and start fondling her breasts."
In 2002, while Rebecca was working for Naomi Campbell in Barcelona, she experienced first hand the supermodel's insatiable craving for cocaine AND women on the same day.
"Kate said she had to go back to the hotel to change," she recalled.
"She said: ‘And YOU'RE coming with me'. So I did.
"When we got to her hotel room, Kate tore off her dress, came up to me in her panties and started kissing me.
"We fell onto the bed together and she touched my breasts, but after a few minutes of groping and kissing, I started to feel nervous and gently pushed her away."
A further source who knows Kate well told us she believed the model's lesbianism went into overdrive after she had secret treatment for alcohol and cocaine addiction at the Priory clinic in Roehampton.
She also says junkie Kate dreams of creating a bohemian "set" among her friends—swapping partners and being bisexual. "Kate sees this as exciting and spicy."
But whereas Kate sees her dream as stylish, other pals realise it is just a drug-fuelled illusion.
"Everyone calls her and her mates Kate and the Disciples," said our source.
"Everyone knows she swings both ways. She is awful for going at it with girls when she's off her head on coke or booze. She would not do it when she was sober."