Licensee Lee De Villiers and friend Simon Clarke kept the barbecue a blaze for 29 hours and one minute, beating the previous record of 28 hours held by a team in Switzerland.
Spectators, including the mayor of Wandsworth, witnessed the start of the two day barbecue marathon at the Young's pub.
Rules stated that a minimum of five items had to be on the barbecue at any given time with sausages, burgers and chicken breasts being continuously prepared throughout.
During the event 500 pieces of meat were cooked and consumed.
Keris De Villiers from the Old Sergeant said: “Breaking a Guinness World Record is a dream for all of us. For the last hour the weather died down and we were all quiet and not laughing and running around, it was almost like everyone was holding their breath- including mother nature.
“When that clock ticked over to 29 hours and 1 minute, 500 pieces of meat later we were all so happy.”