Leona Lewis
Leona Lewis will release some no-holds-barred tracks about Simon Cowell on her new album (Reuters)

Since quitting Simon Cowell's label Syco last year to join rival Island Records at Universal, Leona Lewis has written several tracks on her next album under the new company apparently slamming her old boss.

After winning The X Factor, Lewis worked with Syco for seven years but had reportedly had enough of the control that the label tried to enforce on her, leaving it for good in the middle of 2014.

"It's no exaggeration to say that Leona was driven to the depths of despair by the end of her time signed to Syco," a source close to the Bleeding Love singer reveals.

And it turns out the 30-year-old has chosen to air her feelings on why she decided to leave through her new music rather than any statements or public declaration. The source told The Sun newspaper: "Leona doesn't want to slag anyone off in interviews or on the telly – she wants to let the music do the talking."

One track on the album, entitled I Am features the lyrics, "I am somebody without you, I am free without you, I am stronger without you", while another song, Fire, exclaims "I'm set free. I begin to spread my wings. I'm happy and I've earned it."

"Some of the lyrics sound as if she's talking about a break-up from a boyfriend, but they're actually about leaving Simon," the source continued.

"She had already written most of the album with her song writing partner Toby Gad before she signed the deal with Island. She knew Syco would never have let her release these songs."

The publicly unnamed album will be available to buy in July and will be her first purely original release since 2012, aside from 2013's Christmas, With Love, which consisted of a compilation of covers and tracks created by Lewis.