POP superstars Little Mix have split with mentor and X Factor boss Simon Cowell after an extraordinary row that is rocking the music industry.

The hit girl group — Jesy Nelson, Leigh-Anne Pinnock, Jade Thirlwall and Perrie Edwards — had grown increasingly frustrated with life at his record label Syco over the past 12 months, culminating in fallouts during the making of new album LM5.

6 Simon Cowell has cut ties with Little Mix after extraordinary row that has rocked the music industry Credit: Planet Photos

Little Mix wow as they return to The X Factor and perform Woman Like Me

The girls confronted Cowell direct in a strongly worded email, raising issues they had with his label.

Then a bigger row erupted between the group’s management company Modest and Cowell — who decided to cut all ties with the company’s artists, including Little Mix and last year’s X Factor winners Rak-Su.

The two bands will move to the label RCA, which is also part of the wider Sony group like Syco. A spokesman for Cowell confirmed to me: “Syco Music will no longer work with Modest Management and therefore any artists signed to that management company.

“We do, of course, wish all artists affected by this decision every future success. Consequently, LM5, the forthcoming Little Mix album A&R’d and released on Syco Music, is to be serviced by RCA at the request of Syco and Simon Cowell.”

6 Little Mix had been described as a jewel in Syco's crown Credit: Getty - Contributor

Little Mix put on a sultry and sexy display at MTV EMAs

And band member Jesy summed up the discontent within the band by liking an Instagram post written by @littleshadymix which said of the act: “They’re gonna leave Syco and then tell us what s*** Syco put them through.”

The unprecedented fallout started over Little Mix voicing upset over their lack of recognition on new hit single Woman Like Me.

They wanted an additional writing credit alongside Ed Sheeran, Jess Glynne and songwriter STEVE MAC.

The girls had added lyrics but were not asking for any publishing money.

6 Simon Cowell discovered Little Mix on X Factor Credit: Getty Images - Getty

Cowell got the band the writing credit they wanted, but by that point his relationship with Modest — who also manage the Spice Girls, Olly Murs and Niall Horan — had broken down.

Simon’s decision to cut all ties with Little Mix — the band he created on his ITV show in 2011 and the label’s most successful act — is a massive shock on face value.

But he insisted that he decided to back the loyal staff members who have worked for his Syco label for a number of years and will support Little Mix by inviting them to perform on the X Factor final.

Meanwhile, sources close to Little Mix say the band had clashed with Syco multiple times during the making of the new album.

6 Little Mix appear to have grown fed up of working with Syco Credit: Rex Features

That said, they were still shocked by Simon’s decision to see them leave just days before the release of their highly anticipated fifth album.

However, they accept it’s for the best as they’ll now have a fresh start.

Since One Direction’s hiatus, Little Mix had become the jewel in Syco’s crown.

But the situation also raises questions over Simon’s involvement with 1D should they ever reunite, as Modest manages the boyband.

6 If One Direction ever reform there are now question marks over Simon Cowell's involvement Credit: AP:Associated Press

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Little Mix have sold over 30 million records worldwide, with all four of their previous albums going platinum.

They also boast four No1 singles and nine more Top 10 songs.

6 Little Mix have become one of X Factor's most successful ever acts Credit: PA

The group were formed on The X Factor’s 2011 series after auditioning as solo artists and bagged their first No1 with their winner’s single, a cover of DAMIEN RICE’s Cannonball.

What a surprising end to a powerful pop partnership.