Allen & Overy (A&O) last week sealed its London office entrances after being deluged with abusive phone calls and e-mails from football fans angry at the City giant’s involvement with a bid for Manchester United FC.

The magic circle firm last week (15 October) closed the majority of entrances to its City HQ fearing some form of attack from supporter action groups, who have targeted the firm due to its role as adviser to US sports entrepreneur Malcolm Glazer.