Emap chief executive Robin Miller wrote to Hachette giving notice that Emap wants out of the 10-year partnership.
It is thought that Hachette's decision to bid for Emap rival Attic Futura, publisher of B and Sugar, has triggered the move. There is also understood to have been disagreements over budgets and marketing spend.
If the partnership does end, it is expected that Emap would retain control of New Woman and Red, but lose control of Elle in the UK. Elle will go to Hachette, along with its spin-off Elle Decoration. However, it is less clear which of the publishers will gain control of Elle Girl, which could be the subject of a fierce battle between the two.
Kevin Hand, the former Emap chief executive who was forced to resign after leading the company on a disastrous foray into the US, is understood to have advised Hachette on its £40m bid for Attic.
It is thought by some in the industry that Hand could be keen to redeem himself in consumer publishing, and that the Attic acquisition could be part of his own personal motivation to succeed.
Hand joined Hachette in January and the company bid for Attic earlier this month.
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