In front of a 1,025-strong crowd, the Broncos raced into a 16-0 lead after just 23 minutes thanks to a brace from Iliess Macani and a score in-form half back Oscar Thomas as they inflicted the Centurions’ first defeat since last July.
London’s other tries came from Jamie Thackray and Wes Naiqama, who also kicked four goals, while winger Jonny Pownall scored two tries for Leigh, with Tom Armstrong and Gregg McNally getting the others.
Also at the top, Bradford ensured Gary Thornton endured a torrid first game in charge of Doncaster as they ran out 72-6 winners against the lowly South Yorkshire side.
However the Bulls, entertaining a crowd of 4,982, cut loose in the second half and went on to score 54 further points without reply to record their 14th successive Championship win, keeping the pressure firmly on Leigh at the top.
Williams notched a further three tries while James Mendeika touched down twice on his home debut, with other scores coming through Adam Sidlow, Danny Addy, Etu Uaisele, Adam Henry and Lee Gaskell, with Steve Crossley going over twice.
The Bulls now sit level on points with Leigh at the top of the table, just five points behind the Centurions on points difference.
In Cumbria, Whitehaven hauled themselves back into the fight to avoid relegation with a rousing 28-12 win over Hunslet Hawks.
Haven faced a 12-0 half time deficit after converted tries from Liam Mackay and Richie Barnett at the Recreation Ground. But the Cumbrians turned the tables after the break, scoring four unanswered tries courtesy of Dave Allen, Greg Wilde, Dion Aiye, Richard Beaumont and Jordan Sigismeau, with Louis Jouffret kicking four goals.
James Coyle‘s men now sit eight points clear of bottom club Doncaster and level on points with 10th-placed Batley.
Finally on Sunday, fourth-placed Dewsbury lost ground on the league’s pacesetters when they were held to a surprise 20-20 draw by Workington Town at the Tetley’s Stadium.
However, Jarrad Stack, making his 150th appearance for the club, made it two tries apiece minutes later before Lewis Tierney put the visitors ahead once more. But Joel Farrell crashed over on the hooter to make it 18-14 to the home side at the interval.
Brett Seymour then extended Dewsbury’s lead to six points with three minutes to play, but Workington stole a point at the death thanks to Elliot Miller’s try on the final whistle before Carl Forber held his nerve from the touchline to share the spoils.
On Saturday, Halifax sent out a warning to their top four rivals with an impressive 44-20 away win over Featherstone Rovers.
Gareth Potts and Tommy Saxton both scored hat-tricks, Potts grabbing two of his haul in the first half, as Fax powered into a 26-4 lead. Potts went over for his third late on, while Danny Craven scored twice in the second half with Steve Tyrer also getting in on the act at Post Office Road.
Batley had gone 12-0 up following scores from Lee Mitchell and Shaun Ainscough, plus two kicks from Scott Leatherbarrow, but the Eagles were in determined mood and stormed back with 40 unanswered points, Yere kicking off the comeback with two tries before the break reducing the deficit to two points at half time.
Scores from Sam Smeaton and a pair from Kyle Briggs inside seven minutes of the restart put the visitors clear and they didn’t look back there after. John Davies then went in as Yere went on to complete his treble before the hour with Quentin Laulu-Togaga’e rounding off the rout.