Sir Alex Ferguson once claimed before a European Cup tie in Milan that "when an Italian tells me it's pasta I check under the sauce to make sure". He has chosen his words more carefully ahead of tonight's quarter-final against Roma but Manchester United's capacity for upsetting Italian hosts has resurfaced in the form of an extraordinary diplomatic row.

As Ferguson and his players trained last night on the Stadio Olimpico pitch, United found themselves facing demands for an apology from, among others, the mayor of Rome. He was among those to have been upset by the club's decision to write to their fans, warning them of the "real danger" of being attacked by Roma's "Ultras", and advising them of several areas in the city centre they should keep away from.