Laois escaped from Ruislip with a crucial win to maintain their 100 per cent record in Allianz Football League Division Four.
The O’Moore men deserved their victory but were indebted to forward Gary Walsh, who kicked 11 points while his team-mates floundered in front of goal.
Laois should have been out of sight by the interval, having created a plethora of scoring chances, but they hit 11 first-half wides and found themselves behind at the break when Liam Gavaghan netted from the final play.
Walsh kept the visitors ticking over but a second London goal on 45 minutes, scored by substitute Killian Butler with his first touch, ensured some nervy moments for the sizeable travelling support during the final quarter.
Laois had dropped to second place in Division Four following Carlow’s win on Saturday night but a return to the summit looked a formality as they flew out of the blocks in the English capital.
With John O'Loughlin and Donie Kingston bossing midfield, Laois set up camp in the opposition half, but their dominance was not reflected on the scoreboard.
Laois should have scored 1-4 inside the opening five minutes but remained scoreless due to some abysmal wides and a fine save by London goalkeeper Gavin McEvoy from Walsh’s shot.
London, on the other hand, with economical in front of goal and their English-born trio of Gavaghan, Ryan Elliott and Adrian Moyles saw them lead 0-3 to 0-2 after 19 minutes.
Four successive points from Walsh put Laois in front for the first time but London hit them with a sucker punch in injury time when Gavaghan followed a point with a fantastic finish to the net.
Trailing 1-5 to 0-7 at the change of ends, Walsh didn’t take long to kick Laois back in front but they conceded a second goal after a strong run from Elliott saw Butler bundle the ball home from close range.
London’s lead was shortlived as Laois replied with four unanswered points, three coming from Walsh, but the Exiles remained in contention and trailed by a point as the game entered injury time.
An Evan O’Carroll free put Laois two points to the good but they had to endure some anxious moments at the death as London pushed for a late winner.
Elsewhere in Division Four, Limerick edged out Waterford by a single point on Saturday night, running out 2-10 to 2-09 winners.
The result, which was Limerick's first of the campaign, leaves Waterford rooted to the bottom of the table with just one point.
In Saturday's other game Carlow claimed a comfortable 1-17 to 0-12 victory over Offaly, a result which moved them to the top of the table temporarily, and both Carlow and Laois now sit on 10 points with five wins from five.
Laois: G Brody; S Attride, S Nerney, G Dillon (0-1); T Collins, C Begley, F Crowley; J O’Loughlin, D Kingston (0-1); D O’Reilly, P Kingston (0-1), B Carroll; R Munnelly, G Walsh (0-11, 8f, 1 ’45), E O’Carroll (0-3, 1f).
Subs: E Lowry for Munnelly (49), D Strong for Crowley (49), D Holland for Nerney (55), A Dowling for D Kingston (64), N Donoher for Carroll (68).
London: G McEvoy; P Butler, M Mangan, M Walsh; D Carrabine, Ciaran Dunne, P Begley; A McDermott, J Moran (0-1); L Gavaghan (1-2), M Gottsche (0-2, 1f), S McManus; R Elliott (0-1), L Staunton, A Moyles (0-3, 2f).
Subs: C O’Neill for McManus (ht), K Butler (1-0) for Staunton (44), Colin Dunne for Carrabine (51), C Doran for Begley (66).
