There appear to be two Englands out there, both coached by the same person. The first lot are unbeaten in 17 Tests, still have improvement in them and possess the most influential bench in world rugby.
The second lot are in average form, have injury problems and are starting to be seen as potentially vulnerable. Increasingly, it feels like Dr Jekyll and Mr Hyde are playing in front of the West Stand debenture seats.
If it seems slightly perverse to imagine such a successful side wrestling with a split personality, consider the Six Nations to date. France looked the more impressive team for long periods on the first weekend, only for Ben Te'o to come on and punish the visitors' waning fitness.
Wales would have won in Cardiff but for Elliot Daly's face-saving late try. Italy trailed 17-15 with 10 minutes left before they, too, ran out of gas. Despite the continuing uncertainty over Owen Farrell's left knee, England are collectively fit but dominant 80-minute performances have been absent lately.
What better time, then, for up-and-coming Scotland to be heading south, thermometer at the ready, to gauge the true health of the contrary English patient?
For once it feels less important that the visitors have not won at Twickenham since 1983, when tries were still worth four points and none of today's participants was born. History matters rather less in this instance than what could happen next, particularly if Farrell fails to make it and George Ford is handed the goal-kicking duties.
Diversionary tactics
Interestingly, even England seem a little unsure of what to expect. A seriously confident team would be embracing the record-chasing pressure and be gesturing at their rivals with their fingertips, saying: “Bring it on, if you think you’re hard enough.”
Instead, Jones has had to employ an increasing range of diversionary tactics to steer attention away from the possibility that his side, far from closing the gap with New Zealand, are starting to flatline.
Some of these distractions have been clever, others less so. It takes some doing to alienate the media when England have not lost for ages but there has been increasing friction on that front this week, not all of it unjustified.
While it can be easy to snipe and overlook the doggedness and sheer determination that has hoisted England so impressively from their post-World Cup depression, Jones may have to temper his relentless whip-cracking methods at some stage.
No one is saying he is anything other than a shrewd strategist with zero tolerance for complacency and consistently punchy in front of a microphone, but the Australian has not shown the same sure touch in public since the Italy game.
As long as England keep winning, that barely matters. Over the next eight days, however, Jones and Lions coach Warren Gatland are set to discover if the defending champions are the genuine article or a fading shadow of the side that reigned supreme in 2016.
Worthy adversaries
Should England steamroller a decent Scotland team to win by 20 points and do likewise to Ireland in Dublin on St Patrick’s weekend, even the All Blacks will have to acknowledge their world record for successive Test victories has been beaten by worthy adversaries.
If, on the other hand, Vern Cotter's men win their first Triple Crown since 1990, hoist the Calcutta Cup for the first time since 2008 and rise to fourth in the world rankings, the narrative will start to read rather differently.
There is no shame in regularly winning games late on by the odd point but, at some point, England simply have to start better. If not, the suspicion will grow that their Saracens core – Mako and Billy Vunipola, the injured George Kruis, Maro Itoje and Jamie George – need to be selected en bloc if England truly want to conquer the world in 2019.
Has Ben Youngs done enough to merit another Lions tour? Does Mike Brown still have his old X-factor? Is Jonathan Joseph sharp enough?
Scotland like to throw in the odd tactical curve ball and will pose awkward questions; England had better have some decent answers ready. Take the breakdown where England have mostly toiled until now, hassled by Sam Warburton and Justin Tipuric in Cardiff and temporarily baffled by Italy. In Hamish Watson and John Barclay, Scotland also have men capable of making life tricky in the event of England’s setpiece not grinding the visitors down at source and encouraging the type of hectic, whirling game at which Finn Russell so excels.
Game management
Gatland, one suspects, will take a particular interest in how the confident Russell shapes up opposite Ford in terms of game management and this contest may well determine whether Jonny Gray, or his brother Richie, makes the plane flying the Lions to New Zealand this summer.
Every opponent thus far has also sought out Ford in defence and the Scotland centres Alex Dunbar and Huw Jones look an increasingly dangerous combination. With Stuart Hogg and Tommy Seymour always sniffing for offloads, it will be a surprise if Scotland do not threaten their record Six Nations tally in this fixture of 22 points, set in 2005.
The onus, then, is on England to make their familiar strengths tell and play with power, pace and sufficient control to examine whether Scotland’s pack have the capacity to withstand a prolonged physical assault. England last lost a Six Nations game in March 2015 and should they stretch their sequence to 11 matches, they will eclipse the 10-game streak achieved between 1922 and 1925.
Maybe, though, Jones is thinking one jump ahead. If the past few days have been tense, imagine what next week will be like should England head to Ireland with a chance of becoming the first red rose team to win back-to-back Grand Slams since 1992.
Jones may well be trying to replicate the knock-out stages of a World Cup, with the improving Scots blocking his side’s path to a “final” against Ireland.
It would explain the managerial prickliness and the sudden absence of niceties. England really should win by six to 10 points if they are the team they purport to be. Slip up, though, and all sorts of juicy historical titbits will pass them by. Mr Jones? Dr Jekyll will see you now.
