On the plane to Japan: Johnny Sexton setback emerges to add to troubles in out-half shirt
They know all about problems at No 10 in London right now, but in a southern corner of the English capital the issues Ireland have at No 10 were exposed ruthlessly.
Twickenham is no place to go searching for form and fitness. Nor is it a place for a young out-half to make his first start knowing a good performance would put him in the frame for a World Cup berth.
And yet, it would be harsh to judge Ross Byrne too harshly on what we saw against England.
Joe Schmidt packed the team around him with front-line internationals of huge experience and they played like a drain. The Leinster man never stood a chance.
And yet, the coach needs his third- and fourth-choice out-halves to take responsibility and grow up quickly because there's every chance they'll play a role in Japan.
Reports in a Sunday newspaper yesterday confirmed the suspicion that Johnny Sexton suffered another training ground injury in Portugal.
Having damaged his thumb in June, the latest issue is a leg problem and he is unlikely to be risked in the away fixture against Wales next Saturday and may only feature in the home send-off at the Aviva Stadium a week later.
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With Joey Carbery in a race to be fit to make the plane and also unlikely to play between now and the tournament opener on September 22, Byrne and Jack Carty are important figures in the Irish squad.
The Connacht man might get his chance to impress next week, but it may be prudent to stick with Byrne if Schmidt truly believes he's the man who can best lead the line.
"It was tough for Ross," Schmidt said. "I mean you want to be able to get some set-piece ball on the front foot and Ross didn't get that opportunity.
"Often for a No 10 that's when you start to get a little bit of confidence in the game.
"A tough day defensively as well. He had some big men coming down his channel. He had a couple of really good tackles and he struggled a couple of times as well.
"He wanted to be able to run the game and boss the game but if you don't have the ball it's very hard to boss the game especially when you don't have the ball on the front foot. That was a real frustration."
Few advanced their claims on Saturday and, given Schmidt and Warren Gatland have mapped out a plan for selection for the back-to-back Wales games, it may be a fortnight before we see if lessons are truly learnt. The coach suggested that Dave Kilcoyne, Jack Conan, James Ryan and Keith Earls would return to the selection picture next week to face an experimental Wales team. Cian Healy is highly unlikely to be available after his ankle injury, while Conor Murray may not be risked.
He is also likely to give some fringe players an opportunity. After the way the top dogs played on Saturday, it is a real chance to impress.
For all that Saturday's loss hurt the coach, he's determined to get things right after a performance he described as "dishevelled".
"You're worried no matter what happens, because you're always looking to improve and sometimes when you get that there's lots of things to improve on and they're visible things so you at least have somewhere to go," he said.
"Sometimes you come off a win against the world number one team and people are saying, 'Well, where do they go from here?' and you're asking yourself the same question.
"We've got somewhere to go, we've got two weeks to get there and we've got to really roll our sleeves up and make sure that's exactly what happens."
"I'm not saying we can get back and win against a Wales side which are probably a little bit further down the road than we are but I think in those performance elements I was talking about, I'm really confident we'll see an improvement.
"We've just got to make sure that improvement is sufficient for us to be really competitive and then even more competitive the following week and then as close the peak as we can be against Scotland in four weeks' time."
Eighteen months ago it looked like Eddie Jones' England project was falling apart. Now, they look like real contenders to lift the William Webb Ellis trophy. With ball-carriers who can win the gainline relentlessly, decision-makers of huge quality and pace to burn outside they are stunning when they get going.
Didn't play a minute, but from his home in Cork the Munster hooker put himself in serious contention to start at the World Cup. If he comes in against Wales and the lineout improves while offering more dynamism across the pitch, he's a contender to usurp Rory Best.
It hadn't been perfect before he went off for a Head Injury Assessment, but it all fell apart once the scrum-half was gone. His combination with Johnny Sexton could be key in getting Ireland out of this mess.
Looked every day of his 37 years on a day when the game passed the captain by in open play and the lineout fell apart. Must be at risk.
Trending downwards all year, this was the nadir for a player who trades on his big impacts and delivered none.
When the big moments don't materialise, the numbers don't back him up. Barely had an influence.
His try was stunning, but his defensive decision-making was awful and his work in contact was loose.
Assisted Larmour's try, but he was defensively poor and ran the ball into touch.
His calling hampered a faltering lineout and heaped pressure on Best's poor throw on a day to forget for the forwards.