The Italian told Costa he was not wanted at Chelsea in the ‘Textgate’ affair last summer, when he informed the striker in a phone message that he was not part of his plans for last season.

Chelsea are now understood to have explored legal options about Conte’s actions, with the club believing he devalued Costa’s fee by millions of pounds – as clubs were immediately alerted that Costa might be available.

Conte is due a £9million pay-out for the final year of his contract if Chelsea axe him this summer, with former Napoli coach Maurizio Sarri lined up as his successor, but Chelsea are believed to feel they have a case for compensation over Costa, which could allow them to cut that figure.

Costa was eventually sold by Chelsea to his former club Atletico Madrid for £59m in January.