Chelsea’s negotiations with Bayern Munich over the potential sale of Callum Hudson-Odoi are being complicated by their demand for a buy-back clause. This would stipulate that they could re-sign the 18-year-old England youth winger for an agreed fee. The German champions are reluctant to agree to it.

Chelsea have lost out as a result of their failure to retain a buy-back option in recent years: they missed out on Romelu Lukaku when their former striker joined Manchester United two years ago and paid more than four times the sale price when re-signing Nemanja Matic, the Serbia midfielder, from Benfica in 2014.

Maurizio Sarri, the Chelsea head coach, said yesterday that Bayern had been unprofessional in making public their desire to sign Hudson-Odoi and that they