Billy Twelvetrees knew all about the unpredictability of the French midfield as England embarked on their Six Nations campaign in Paris last month, so when the brilliant young Toulouse centre Gaël Fickou reduced the red rose cover defence to a state of advanced discombobulation in the closing seconds – his match-winning try remains the most memorable individual act of the tournament to date – the Gloucester man was distraught, but not wholly surprised. By contrast, he knows precisely what to expect from Wales this weekend. Not that it will make life any easier.
Twelvetrees is about to come face to face with Jamie Roberts, the British and Irish Lions' first-choice inside centre in South Africa in 2009, and again in Australia last summer: the clearest possible indication of the esteem in which the Welshman is held at international level.
His reputation in this most confrontational of team sports is built on twin foundations: sheer physical size – at 6ft 4in and well over 17st, he could easily cut it as a back-five forward – and an ability to run hard and straight at a considerable rate of knots. While Fickou flies, Roberts flattens.
If Twelvetrees is himself built on a scale significantly more substantial than England's centres of old – you could scour the earth and struggle to find a 6ft 3in midget – his ability to stand tall and firm in the face of serious poundage has not always convinced the tougher-minded members of the coaching fraternity.
During his spell at Leicester, he was considered a little soft (although in fairness to him, Attila the Hun would have been considered too conciliatory at Welford Road); during his time with England, he has had to work hard to convince Andy Farrell, the defence strategist, of his value when it comes to manning the barricades.
Yet in the victory over Ireland at Twickenham 12 days ago, he tackled his heart out, recovering from an early slip against a pumped-up Brian O'Driscoll to play a leading role in a determined defensive effort.
If Twelvetrees emerges in one piece from his tangle with Roberts on Sunday – a very different kind of examination, if not a particularly complex one – he will take a big stride towards securing his place in England's squad for next year's World Cup.
"In a sense, nothing changes, because in modern rugby you have big guys running at you all day long," he said. "I've never faced Jamie in a match, even at club level, but in terms of physicality I think this will be the biggest challenge I've faced."
It was no mean statement, given his head-on meeting with the formidable All Black midfielder Ma'a Nonu before Christmas.
"Jamie has shown over the years that he's a top-class player and a good professional – one of the people you look up to," said Twelvetrees. "We know what's coming, so it's important for us to get ourselves on the front foot straight away. Rugby is a battle, mentally as well as physically, so we need to deal with the situation by making dominant tackles. I think we did that against Ireland, particularly when we were under pressure towards the end and managed to stay connected, stay in the system and stay switched-on."
In Wallaby country nine months ago, the Lions summoned Twelvetrees from red-rose business in Argentina when Roberts broke down with injury. The Englishman took what he could from the experience, despite being a bit-part player, and returned home with a clearer idea of the demands of the union game at its top end.
He also had a ringside seat for one of the great controversies of the trip: the decision of the tourists' coach, Warren Gatland, to drop the sainted O'Driscoll from the final Test in Sydney; pick one Welsh centre, Jonathan Davies, in his place; and choose another, the fully recovered Roberts, as his partner.
The roles will be reversed at Twickenham, where Davies will be the one fast-tracked into the Wales midfield after injury, alongside Roberts, who is mining a rich seam of form. "I think a lot of players in the Lions squad regarded Jonathan as one of the outstanding players on the trip," said Twelvetrees, who, it seems, was not as flabbergasted as some by Gatland's bold call in selection. "He deserved his place in the side. He's an excellent defender with a very strong left-footed kicking game."
Stuart Lancaster, the England head coach, has confirmed that the Exeter back-rower Tom Johnson, outstanding in his club's Premiership victory over London Irish last weekend, would fill the vacancy on the bench caused by Billy Vunipola's ankle injury and the promotion of Ben Morgan to the starting line-up at No 8.
Two players, the Wasps prop Matt Mullan and the Leicester centre Manu Tuilagi, will continue to train with the 23-man squad.