Manchester City may have to pay a world record fee for a defender if they are to succeed in their efforts to sign Leonardo Bonucci this summer, with Juventus continuing to adopt a hard-line stance over the coveted Italy centre-half.

City enquired about purchasing Bonucci last summer after failing to sign Aymeric Laporte from Athletic Bilbao only to be put off by Juventus’s £50 million valuation of a player who turns 30 a week on Monday.

Nonetheless, Bonucci remains Pep Guardiola’s priority defensive target as the manager bids to bolster his back line in what is expected to be a huge overhaul of City’s playing squad during the close season.

Chelsea and Manchester United also harbour an interest in Bonucci, and with the player having more than four years to run on the new contract he signed in December, there is a grudging acceptance that his price is likely to remain high, despite tensions in his relationship with the Juventus coach Massimiliano Allegri. Any deal could threaten the world record £50 million fee for a defender that Paris St-Germain paid Chelsea David Luiz in 2014.