The Broncos have been showing signs of significant improvement under new coach Joe Grima, having run Huddersfield and Catalan Dragons close in recent weeks.
And while they threatened to mount a comeback in the second half after reducing a 22-4 deficit to just six points, they were ultimately left to rue defensive lapses as the Robins earned their second successive win.
On-loan St Helens winger Ade Gardner, Craig Hall and Josh Hodgson touched down twice while there were also tries for Neville Costigan, Adam Walker and Kevin Larroyer, with Travis Burns adding six conversions as Craig Sandercock’s men moved back into the play-off places.
It was a cagey opening from both sides, with the hosts particularly guilty of several handling errors. Yet once they hit their stride in the 17th minute, they never looked back.
An initial burst down the right from Kris Keating laid the perfect platform for Hull KR and they duly took advantage as Costigan off-loaded to Hodgson to touch down for his sixth try of the season.
From grounding his side’s second try immediately afterwards yet the hosts would not be denied as from the next set of six, Costigan went over under the posts.
London got on the scoreboard when Danny Solomona dived over on the left after collecting a short pass from Scott Moore, but their deficiencies were exposed once again when replacement Walker pierced another gap in to score on his return from injury.
The visitors were split once again when Ben Cockayne cleverly dummied from deep and with London struggling to regroup, Gardner did well to take Burns’s pass wabove his head to touch down in the right corner, Rovers going in at the interval with a comfortable 22-4 lead.
Yet they were grateful for two wasteful errors from London either side of half-time.
After missing two chances to score, the Broncos kept up the pressure, however, and were rewarded when loose forward Alex Foster touched down.
Clearly buoyed by their score, London continued to push forward and Foster had his second try after James Cunningham had cleverly jinked his way through a static Hull KR defence.
Once more, though, London conceded possession deep in their own half after a knock-on, and a flowing move along the right ended with Larroyer scoring Hull KR’s fifth try.
London’s hopes of overhauling the deficit appeared over once Gardner scored his second try as Hull KR finished with a flourish thanks to two tries from Hall and one from Hodgson.
Hull KR: Cockayne, Gardner, Salter, Welham, D. Hodgson, Burns, Keating, Netherton, J. Hodgson, Weyman, Larroyer, Horne, Costigan. Substitutes: Hall, Langley, J. Walker, A. Walker.
London Broncos: Farrar, Atkins, Caton-Brown, Minns, Solomona, Cunningham, Drinkwater, Slyney, Moore, Krasniqi, Vea, Cook, Foster. Substitutes: Griffin, Bishay, Greenwood, McMeeken.
Referee: R Hicks (RFL).