The visitors were the better side by a mile on the day, full value for their win and in no way flattered by their 14-point winning margin.
It was a shocking display and performance by Offaly, who got nowhere near the level they needed but London deserve all the praise for the way they played.
They defended in numbers, frustrating Offaly in the first half, and attacked at great pace. While Cathal Donoghue gave Offaly the lead after a minute, it was clear that they were in difficulty from early on. London got the next four points, three of them from man-of-the-match Ciaran Diver.
Offaly got three-in-a-row to level it up after 20 minutes while Keith O’Neill had a goal questionably ruled out for over carrying. London got the next three and fully deserved their 0-8 to 0-6 half time lead.
Quick points from Aidan McLoughlin and the excellent Shay Rafter put London four ahead by the 37th minute and they never looked like losing from here. They led by four points on three more occasions and a scrambled 49th minute goal from Stephen Dornan put them 1-13 to 0-9 ahead.
London played their best football after this, opening Offaly up and Diver’s 65th-minute goal gave them a 2-17 to 0-12 lead. Offaly had sub Dan Molloy red carded a minute after coming on in the 67th minute and while it was an absolutely terrible day at the office for them, this was all about a famous London success.
London scorers: C Diver 1-5 (3f), S Rafter 0-4, S Dornan 1-1, D Clarke, R Rafferty and J Obahor 0-2 each, E Walsh, A McLoughlin, L Gallagher (f) and M Carroll 0-1 each.
Offaly scorers: D Hyland 0-4 (2f), J Bryant (1f) and N Dunne (1f) 0-2 each, I Duffy (’45’), P Cunningham, E Carroll (mark), C Donoghue 0-1 each.
OFFALY: I Duffy; L Pearson, D Dempsey, J Furlong; C Egan, P Cunningham, R Egan; E Carroll, C Donoghue; D Hyland, C Flynn, J Hayes; C Farrell, K O’Neill, J Bryant.
Subs – J O’Brien for R Egan (42m), N Dunne for Flynn (44m), R McNamee for Farrell (47m), N Poland for Donoghue (50m), D Molloy for Dempsey (66m), .
LONDON: A Walsh; E Walsh, D Rooney, C McKeon; O Kerr, S Rafter, A McLoughlin; S Dornan, L Gallagher; M Carroll, D Clarke, C Diver; J Obahor, R Rafferty, F Eastwood.
Subs – M Miller for Kerr (57m), C Healy for McLoughlin (60m), T Barry for McKeon (63m), DJ O’Flaherty for Rafter (63m), J McGill for Rafferty (71m),
Referee – D O’Mahoney (Tipperary).