Adam Field netted a hat-trick for Britannia but his side needed to stave off a Lions fight back to seal the silverware.
The Lions bossed the first ten minutes, but Field opened the scoring with a 25-yard drive over the advancing Haxby keeper on 14 minutes.
Haxby’s Matty Wash went close on 19 minutes when his shot from an acute angle was palmed away by Britannia keeper Jordon Tinker.
Further Haxby pressure saw winger Joe Galloway cross from the left only for Sam Wood to blaze a shot over the bar from ten yards.
Britannia upped their game, having two shots saved before Field latched on to a through ball to hammer home from 20 yards on 36 minutes.
Haxby pulled a goal back on 42 minutes as Tom Matthews put through Wood to finish from close range.
Britannia extended their lead to 3-1 after the break when Field turned provider, crossing the ball to Ryan Ferguson who slotted the ball into an empty net.
Field completed his hat-trick on 66 minutes when he took a quick free-kick from 20 yards as the Haxby defence was statuesque.
Wood scored his and Haxby’s second on 74 minutes and was denied a treble on 83 minutes following a save by Britannia keeper Tinkler.
Joe Galloway set up a nervous last two minutes when he scored Haxby’s third from a tight angle, Britannia ruled at the final whistle.
The trophy was presented by Martin Richardson, of sponsors Richardson’s Butchers of Woodthorpe.
Meanwhile, Ian’s Cars of Barlby first division champions King William completed their season with a 4-0 win over Dunnington. Neil Ducey got the champions off to a flying start when he netted after only two minutes.
Two further goals followed to make it 3-0 at the break, the pick of the two being the goal that gave them a 2-0 lead, after an eight man passing move culminated in Tom Hawksby crossing for Kevin Butler to head home a powerful header. Dunnington started to get back in the game in the second period but Nathan Kamara broke from his own half out pacing the defence to slot the ball into the bottom corner of the net to make it 4-0. King William’s third goal coming from Tom Hawksby.
Leeman United were crowned champions of division two after beating relegated Beeswing 4-2 in mid- week. United 1-0 down early on equalised with a strike from Ollie Newby, they then went 2-1 up with a free kick from Mike McKenzie. Lee Pallender with a header doubled the lead before Newby scored his second and United’s fourth for 4-1. Wing pulling a late goal back to set up a nervous final moments for Leeman.
Huntington Rovers who pushed the leaders all the way completed their season with 3-2 win over visitors Hambleton with a brace from Danny Franks and an Andy Brabbs effort to finish runners up. Rovers who won their last three games on the bounce including a 6-2 win over York Nomads with braces from Lee Bunce, Danny Franks and strikes for John Patrick and Chris Horwell. They also hammered basement side York Medics 13-0, a result that saw them claw back an inferior goal difference from the champions.
Hemingbrough finished their season with a 2-1 home win over York Medics. The home side went 1-0 behind early on but were all square before the break with a goal from Adrian Wood. Callum Ransome netting the winner in the second period.