I have no idea which France will turn up, says their own (English) coach

Yorkshireman Ellis is in charge of French defence but even he cannot predict if Les Bleus will be red hot or a rabble

Marc Lievremont's one-liner about his French team "failing to get off the bus" for what turned out to be a chastening defeat by Tonga last weekend is rightly being lauded as one of the more piercing comments of this World Cup, but the real question about Les Bleus ahead of the quarter-final with England in two days' time is not how they travel, but where they reside. "Will the players be in the basement or the penthouse?" asked their defence coach, Dave Ellis. "Who can tell? They move from one to the other so quickly."

Ellis, a common-sense rugby league type from Yorkshire whose links with the union game in France were first forged in Paris and Bordeaux, was always going to face intense questioning when he poked his head above the parapet yesterday – partly because any English perspective on the mysteries of Tricolore rugby is valuable, especially ahead of a game like this, and partly because Lièvremont, his immediate boss, has become one of this tournament's more extraordinary figures.

"Look, Marc wears his heart on his sleeve," said Ellis, responding to questions about the head coach's open criticism of, and fractured relationship with, the players – not just those he has dropped, like the outside-half François Trinh-Duc, but those who have belatedly emerged as the leaders of a generally leaderless group, like the back-row forward Imanol Harinordoquy and the scrum-half Dimitri Yachvili. "Some of the things he has said about players have been totally justified," he continued. "When you have a bad game, you don't like people telling you. Marc has told them, and he's done it in public because he's an open sort. There was criticism when he was first appointed to this job that he didn't have a great deal of experience at a high level, but he has done some fantastic work."

Interestingly, Ellis is pleased with the twice-defeated French from the defensive perspective: indeed, he was deeply impressed by some of their "scrambling" – the term used for last-ditch tackling when the line has been broken and the intricately-planned structure is no longer in place – in the match against Tonga, even though the final result left both the players and the coaches open to a torrent of mocking abuse from every rugby stronghold between Paris and Perpignan.

While England held another light training session yesterday – this one involving the much-maligned centre Mike Tindall, who had made significant progress in recovering from the leg injury he suffered during last weekend's narrow pool victory over Scotland – the Tricolores were piecing together a plan of action they believe has the potential to earn them a first World Cup victory over their most implacable foe since the play-off for third place in South Africa more than 16 years ago.

"Forget the pool games," said Ellis. "If you look at northern hemisphere rugby over the last decade, France have been the most consistent team. While I've been involved, we've won five Six Nations titles and three Grand Slams. But it is in the culture of these players that they rely on a flood of emotion to raise their performance to the top level, and if you look at our four games in the group stage, they didn't find a way then of bringing that emotion to their rugby. Now we are in the quarter-finals, I think you will see something more, something different.

"England haven't shown a great deal either, but they've been winning. It's often the way with them: certainly, when we won our last Slam in 2010 with rugby that was more organised than exciting, we took that from England. What needed to be done when I first became involved was to bring standards up to world level on a regular basis, and that meant improving discipline. Maybe we became so intent on not conceding penalties, we allowed some of the aggression to disappear from our game. We need to bring that back."

By comparison, Yachvili was less forthcoming – perhaps because he was saving his best words for the dressing room at Eden Park on Saturday. He was, however, willing to list what he considered to be England's principal strengths. Needless to say, the adventurous handling game did not receive a mention. "I am always impressed by them because they have good basics: a big scrum, a functioning line-out, strong defence, Jonny Wilkinson at No 10," the Biarritz goalkicker said.

"Now, they also have [Manu] Tuilagi, who is a very positive player because he breaks the line a lot. To win, we will have to be better than them in the forwards. If you are in a quarter-final or a semi-final, any knock-out game, and you can retain possession, you are in a position to beat anyone. Maybe their mentality has been better than ours [so far in the tournament], but this is a World Cup match and we are all ready for it."