GB coach Tony Smith was given plenty to think about in the game
Northern Union: (5) 18
Tries: McGuire 2, Clarke, Yeaman
Goals: Rooney 3
All Golds: (15) 25
Tries: Lauitiiti 2, Eastwood, Anderson, Toopi
Goals: Jones 5
* Tries - 3 points; Goals - 2 points
Second-half tries from Louis Anderson and Clinton Toopi sealed victory for the All Golds over the Northern Union in the Centenary International.
Stacy Jones kicked five goals in his last game before retirement.
Danny McGuire scored a try in each half for the Northern Union while Jon Clarke and Kirk Yeaman also went over.
However Yeaman injured ankle ligaments while scoring and may be ruled out of contention for the Test series against New Zealand which begins next week.
Captain Adrian Morley and second-rower Danny Tickle were both placed on report for alleged high tackles to give coach Tony Smith some moments of concern before he names his Test squad on Sunday.
Although it was McGuire who gave the Northern Union an early lead with a try converted by Jamie Rooney, his Leeds team-mate Ali Lauitiiti hit back with two quickfire efforts to put the visitors in control.
Another try by Greg Eastwood, also converted by Jones, extended their advantage just before the break with the Northern Union struggling at times to cope with the power of the All Golds.
The Northern Union began the second half strongly with Bradford teenager Sam Burgess putting in a good display which earned him the award for man of the match.
McGuire then took a lovely inside pass from Yeaman to go over before Clarke scored on his club ground and Yeaman took advantage of a break from Terry Newton to put his side 18-15 ahead.
But Anderson and Toopi sealed the win with Jones bringing down the curtain on his career in appropriate fashion by adding the extras for both.
Great Britain coach Tony Smith
"We're not happy about coming second, that's something that has got to change. That's one message for ourselves we'll be taking out of it.
"The players who make the cut will benefit from tonight, both from the physical aspect and from the lessons on how to play.
"Even the guys who do not make it will take the experience and now know the step they have to take to go to the next level.
"There were plenty of positives. There were some great players who have gone out on a positive note."
Northern Union: Platt (Bradford); Hodgson (Huddersfield), Martin Gleeson (Warrington), Yeaman (Hull), Raynor (Hull); McGuire (Leeds), Rooney (Wakefield); Morley (Warrington, capt), Newton (Bradford), Lynch (Bradford), Tickle (Hull), Burgess (Bradford), Wild (Huddersfield).
Replacements: Clarke (Warrington), Moore (Wakefield), Coley (Wigan), Sykes (Bradford).
All Golds: Perrett (Sydney Roosters); Kenny-Dowall (Sydney Roosters), Vagana (South Sydney), Toopi (Leeds), Tupou (Bradford); Leuluai (Wigan), Jones (Catalans); Price (NZ Warriors), Faiumu (North Queensland), Wiki (NZ Warriors, capt), Lauitiiti (Leeds), Kidwell (South Sydney), Anderson (NZ Warriors).
Replacements: Eastwood (Brisbane), Lauaki (NZ Warriors), Guttenbeil (Castleford), Stanley (St George).