Manchester United are considering making Kalidou Koulibaly the most expensive defender in history in January.

Jose Mourinho has already had two bids for the Napoli player rejected as he looks to bring in a world-class centre-back in the New Year.

United are now weighing up a third approach, with Napoli believed to be holding out for around £100million for the in-demand 27-year-old.

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Koulibaly was one of a host of central defenders recommended to Mourinho by former scout Javier Ribalta last summer.

But United focused their attentions on Toby Alderweireld, Harry Maguire and Jerome Boateng - ultimately ending up empty-handed, much to the frustration of Mourinho.

Now the under-pressure United manager wants the funds to salvage the season when the transfer window reopens, with a centre-back his priority.

Executive vice chairman Ed Woodward has made it clear to Mourinho that the money is there to usurp the £75m Liverpool paid for Virgil Van Dijk last January if the right candidate becomes available.

But the club’s hierarchy have also told their manager they will be prepared veto him in the market, just as they did in the summer.

Koulibaly is not the only defender in Mourinho’s sights.

United have a long-standing interest in Alderweireld, have not given up hope of landing Maguire, while Inter’s Milan Skriniar is another they are monitoring closely.

Mourinho is also an admirer of Alessio Romagnoli.

Woodward is aware Alderweireld will be available for around £25.4m in the summer, so a compromise deal could be there to be made with Tottenham next month.

Meanwhile, the failure of Napoli and Inter Milan to reach the last-16 of the Champions League should boost United’s chances of landing Koulibaly or Skriniar.

Mourinho’s continued pursuit of a top-class centre-back casts further doubt over the futures of Eric Bailly and Marcos Rojo, who could both be sold in January to make way for a new recruit.