Wales, who marched past Scotland on Saturday, face their arch-enemies at the Millennium Stadium this Saturday.
The reigning champions can still defend their title and wreck England’s hopes of a first Grand Slam in a decade.
Howley said: “It’s one of the biggest games any of our players or coaches will be involved in.
“If England do what we think against Italy they will be coming to our stadium, in front of our supporters trying to win a Grand Slam.
“We had great experiences when we won the Triple Crown in England last year and they will be backing themselves against us. It’s a mammoth game.
“The boys can be very proud of the character they have shown away from home in the last three games. It gives us a lot of momentum ahead of that game.”
Howley was disappointed with Wales’ discipline at Murrayfield – as a Six Nations record for penalty attempts was set.
But he was thrilled with the performances of Sam Warburton. The flanker had been criticised for a string of under-par performances and was relieved of the captaincy duties.
But he proved his critics wrong with a colossal performance, which will strikefear into England. The under-pressure ace snatched at least three key turnovers and made 13 thumping tackles – more than anyone else on the pitch.
Howley said: “Sam was outstanding. He has world-class qualities, put pressure on the ball and got vital turnovers.
“I’m delighted for him because he’s had a tough time. It’s good to see him playing and enjoying rugby.
“He’s a very mature, grounded individual and you would expect that response.
“He proved the people questioning him wrong with that outstanding performance.”
Warburton could regain the captain’s armband for the clash with Stuart Lancaster‘s men with Ryan Jones a doubt.
The stalwart flanker injured his shoulder and was taken off after 48 minutes of the victory.
Wales remain optimistic that Jones will be fit for the Championship finale and also hope Gethin Jenkins will recover from his calf injury.
Howley said: “Ryan has taken a contact to the shoulder and will be assessed. We will take judgement from there. At the moment we’re hopeful of him being fit.”
Wales’ win stretched Scotland’s losing streak to their Celtic rivals to six and Scott Johnson was left bemused by referee Craig Joubert’s officiating of the scrum.
He added: “I was as confused as anyone about what was going on. The frustrating thing was that we got to play off nothing.
“We got our first lineout in the second half and while we think we have a competitive scrum, we are getting nothing from it and have done so for three weeks.
“We have a world-class front row and we scrum square.
“We don’t try to do any tricks and our scrum coach is adamant that is the case.
“We have been around the houses with this scrum issue. I have spoken to the IRB and Craig before the game.
“It was strange for him because when you look at his statistics he notoriously gives the least amount of penalties at the scrum. So it was an odd day at the office for him.”
MIKE BROWN