WALES' two-year reign as RBS 6 Nations champions reached its conclusion in Cardiff - but not before they went on a record-breaking 51-3 rampage against hapless Scotland.

The Scots were battered beyond recognition after full-back Stuart Hogg was sent off midway through the first half, which followed skipper Kelly Brown's departure through injury.

And Wales, hurting from emphatic title-ending defeats against Ireland and England this season, did not require a second invitation to cut loose with seven tries at the expense of 14 men.

Wing George North and centre Jamie Roberts each claimed try doubles, while there were also touchdowns for full-back Liam Williams, number eight Taulupe Faletau and substitute scrum-half Rhodri Wiliams to mark prop Gethin Jenkins' record 105th Wales cap in style.

Fly-half Dan Biggar added to the rout by kicking 14 points and James Hook booted a late conversion, with Scotland only managing an early Greig Laidlaw penalty in reply.

It was Wales' all-time biggest Six Nations win, surpassing a 47-8 stroll past Italy in 2008, and a record victory over Scotland as their interim head coach and ex-Wales caretaker boss Scott Johnson endured a miserable final Test at the helm.

Johnson will hand over to New Zealander Vern Cotter this summer, and the size of Cotter's task was graphically underlined by a Wales team that showed no mercy.

The Scots unravelled once Hogg was dismissed. He initially received a yellow card from French referee Jerome Garces for hitting Williams in the face with his shoulder, but Garces changed his mind and brandished red once he watched television replays.

It was a brave, but legitimate and correct call by the official, and Scotland never recovered as Wales punished them ruthlessly.

Wales showed six changes from the side beaten at Twickenham last weekend, including rare starts for hooker Ken Owens and prop Rhodri Jones, while Williams filled the full-back vacancy created by dislocated shoulder victim Leigh Halfpenny.

Scotland's three switches, meanwhile, were all injury-enforced as wing Doug Fife made his Test debut instead of Tommy Seymour, Max Evans replaced Sean Lamont on the other wing and flanker Ryan Wilson deputised for Johnnie Beattie.

Laidlaw and Biggar exchanged penalties inside the opening 10 minutes, but Scotland were rocked by Brown's early departure through injury after he was hurt in a tackle. Alasdair Strokosch took over off the bench.

Brown's exit understandably disrupted the Scots, and Wales hit them with a 16th-minute try after they went through several attacking phases before the visitors ran out of defensive numbers and an unmarked Williams dived over.

Biggar converted brilliantly from the touchline, and Wales were up and running, 10-3 ahead as they started making their presence felt at the breakdown area, especially.

Scotland then hit the self-destruct button as Hogg was rightly punished following his reckless challenge on Biggar.

Hogg could have no complaints as he became only the third Scot in Test match history after Nathan Hines and Scott Murray - Murray was also dismissed against Wales in Cardiff - to be sent off.

Biggar dusted himself down to kick the resulting penalty, leaving Scotland to embark on a prolonged damage-limitation exercise.

But there was no sign of them stopping the red tide as Wales added a second try seven minutes before the break after Williams counter-attacked from deep, scrum-half Mike Phillips acted as link man and North sprinted away to score.

Biggar's conversion made it 20-3, and Wales were only denied a third touchdown when Garces disallowed it after Faletau roamed offside in front of a kicker.

Another score duly on the stroke of half-time, though, with more slick Welsh handling resulting in Jonathan Davies delivering a scoring pass to his midfield partner Roberts, and Biggar's conversion took the home side out of sight.

It took Wales just 58 seconds of the second period to move past 30 points, and it was another try of simple execution as the impressive Davies merely drew his opposite number before firing out a scoring pass.

Predictably, matters deteriorated further for Scotland as Roberts claimed his second touchdown following a stunning 80-metre move that heavily involved Faletau, then Faletau added try number six with almost 30 minutes still remaining.

And it was Rhodri Williams who completed the scoring when he capitalised on a clever kick by Hook, meaning that Wales scored 41 unanswered points after Hogg was dismissed.

ends