Steve Bucknall, despite suffering from food poisoning, was the catalyst in London's win, which hinged on outscoring Sheffield 18-2 either side of half-time. It is hard to see Sheffield recovering to dislodge London from the top of the table when the league resumes next weekend.
Sheffield lacked London's balance and apart from Roger Huggins, who scored 14 first-half points, only two other players scored a single field basket each before the interval. On the restart, Sheffield's hopes were immediately quashed as Martin Henlan, Tony Windless and Bucknall's three-pointer gave London their biggest lead of 19 points.
The National League's First Division champions, Crystal Palace, defended their National Trophy title with a 64-51 win over Coventry Crusaders - their 50th consecutive victory against National League opposition.