* Wales romp to record 30-3 victory
* Two tries for flying winger Cuthbert seal title
* Outclassed England miss out on grand slam again (Adds quotes)
CARDIFF, March 16 (Reuters) - A rampant Wales delivered the command performance a rocking Millennium stadium demanded when they overwhelmed England by a record 30-3 scoreline to retain the Six Nations title and deny the visitors a grand slam on a memorable evening on Saturday.
Wales began the game wondering if they could somehow fashion a seven-point victory to wrest the title away from England. Instead, with two second-half tries by winger Alex Cuthbert, they produced their biggest victory over their fierce rivals with the 27-point margin surpassing the 25-0 win chalked up in Cardiff 108 years ago.
The Welsh, under fire from all sides when they fell to an eighth successive defeat when beaten by Ireland on the opening weekend of the tournament, led 9-3 at halftime with three Leigh Halfpenny penalties before cutting loose after the interval to outclass their rivals.
"This is better than the grand slam last year," interim Wales coach Rob Howley told the BBC.
"We outclassed England. We kept sending the message that good teams don't became bad teams overnight. This is a unique place in world rugby. With the crowd behind us, we needed to start well."
Wales had not conceded a try since the 42nd minute of their opening week defeat by Ireland and, had they woken up at kickoff instead of just after halftime in that match, they could well have been celebrating a second successive clean sweep.
Regret, however, was not the dominant emotion as thousands of fans set off singing into the Cardiff night.
Cuthbert, who also scored tries against Ireland and Italy, showed all the speed and determination that England's attack lacked. "We worked a heck of a lot over the last few weeks and it worked out well, we couldn't ask for anything better," he said. "We didn't want to let go of that trophy."
England, who struggled to get past Italy last week, can have no complaints about the result having failed to impose themselves on any aspect of the game and eventually being blown away.
Head coach Stuart Lancaster accepted that Wales were the better side but could not explain how England fell away so dramatically.
"Going into halftime, we realise we hadn't got all the execution right but we still felt we were going okay," he said.
"But the start of the second half wasn't good enough and Wales thoroughly deserve the win. I don't think it was a psychological thing. Wales played well and we didn't turn up and we didn't match their physicality."
England's defeat joins the list of previous grand-slam failures, including three in a row from 1999 and another in 2011. On that occasion in Dublin there was at least the consolation of their first title since 2003 but this time the victor took the spoils in a dramatic, floodlit presentation ceremony.
With the roof closed and the crowd fuelled by a long afternoon in the pubs clustered around the stadium, Wales were well-worth their 9-3 halftime lead.
At the start of the second half a 23-phase forward assault on England's line earned Halfpenny another penalty which he slotted to put Wales 12-3 ahead and, for the first time, go beyond the eight-point margin needed to take the title.
If the home fans were happy with that, they were delirious soon after when another midfield turnover set up Cuthbert to show his fantastic finishing ability by scorching round Mike Brown with a timely handoff before gleefully diving over in the corner.
England were in disarray and after Dan Biggar slotted a drop goal Cuthbert sealed the victory following great work by flankers Justin Tipuric, who was named man-of-the-match, and Sam Warburton.
"It's a bit unreal. I think it's a dream to be honest. I never really thought we'd play so well in front of a great crowd," Tipuric said.
"The boys were outstanding. We knew what we could do. We've been ready since Monday. To turn up with such a great performance, we're chuffed to bits."
(Editing by John Mehaffey)