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Every successful side must have a strong spine. Strong players but also strong decision-makers because the spine embraces those by whose form the team as a whole will stand or fall — from hooker, through the No 8 to the half backs and, finally, full back.

This is what Martin Johnson has been seeking since he became England team manager 15 months ago — a hard core of players around whom he can build a side to be measured against the World Cupwinning squad he led as a player. Individuals with experience, preferably, but also with that dependable quality: the ability to maintain a standard no matter the opposition.

Think of the spine that won the World Cup in 2003: Steve Thompson and Lawrence Dallaglio in the forwards, Matt Dawson, Jonny Wilkinson and Josh Lewsey in the backs, of whom Lewsey was a relative newcomer but busting with character and resilience.

It was noteworthy, too, that when England reached the 2007 final, they went back to the same generation, to Mark Regan and Andy Gomarsall to go with Wilkinson and Lewsey, who shared the full-back duties with Jason Robinson. The only newcomer was Nick Easter, the Harlequins No 8.

It is Johnson’s job to establish a side with similar backbone in time for the 2011 World Cup, although, because he lives in the here and now, the former lock could do with them rather earlier than two years’ time.

But as he looks at the potential squad that will do duty during next month’s Investec Challenge Series matches against Australia, Argentina and New Zealand, he can identify only two of his five and one of those, Wilkinson, has been prey to so many injuries over the past five years that Johnson must be fearful of trying to build anything around him.

Not just Johnson. His predecessors, too, have been hampered by unavailability, usually through the kind of injuries that have proved so debilitating this season. Identification of the necessary talent is one thing, keeping them fit and ready for action quite another; so when Johnson sits down with Brian Smith, his attack coach, and the rest of his coaching panel to come up with a revised senior squad on Monday, he is looking at a potential back division from which five players have been ruled out, along with four more from the England Saxons squad.

Who, then, are the three core backs to take England forward against Australia at Twickenham on November 7? Self-evidently, Wilkinson is at the heart of it at fly half; Johnson places huge trust in international rugby’s record points-scorer, the man whose dropped goal beat Australia in Sydney in 2003 and, at last, Wilkinson has put together the run of games for his new club, Toulon, which justifies his return to England colours for the first time since March 2008.

It is also fair to say that Johnson is not exactly spoilt for choice: Toby Flood has not played this season because of a ruptured Achilles tendon and, of the Saxons fly halves, Danny Cipriani and Sam Vesty are injured, while Stephen Myler has only just returned for Northampton after five weeks out.

Indeed, if Wilkinson, heaven forbid, fell under a bus today, the most likely replacement would be the man earmarked to be his inside centre, Shane Geraghty, promoted from the Saxons. And if Johnson wanted to keep Geraghty in the No 12 shirt, the chances are England would fall back on Andy Goode, who is familiar with the system that Smith and Mike Ford, the defence coach, want to operate.

If Wilkinson, then, is nailed on, his partner at scrum half is not. Harry Ellis has the benefit of a Lions tour behind him, but a dodgy knee will keep the Leicester No 9 on the sidelines. That leaves Danny Care and Paul Hodgson battling for the honours and although Hodgson has been at the top of his form with London Irish this season, Care is more likely to get the nod.

It comes down to a matter of investment. Johnson’s watchword is consistency; Care was part of his squad throughout last year, he learnt from one or two expensive errors and he is the sitting tenant, having started both internationals against Argentina in the summer. He also has that X-factor: speed on the break that will keep opposing back rows honest.

Hodgson is as good a defensive scrum half as there is in England and Smith knows him well, having worked with him at London Irish, but in Care’s favour there is also his club understanding with Easter, who is certain to play No 8.

The picture at full back is clouded by the injury that will keep Delon Armitage out of the autumn games. Olly Morgan can be discounted, too — the Gloucester player has taken too long to recover from a hamstring problem — which leaves England veering towards Ugo Monye.

They have no other specialist full back in the senior squad, while the Saxons offer Nick Abendanon and Ben Foden, but if Monye is to be switched from the wing to full back — where he has proved strong under the high ball for Harlequins — that gives the coaches the chance to field Mark Cueto and Matt Banahan on the wings.

It is something of a gamble, but Monye exudes such confidence in the wake of his Lions tour that it is one England seem willing to take.

Fit club: the backs

England senior squad Available Matt Banahan (Bath) Danny Care (Harlequins) Mark Cueto (Sale Sharks) Dan Hipkiss (Leicester) Paul Hodgson (London Irish) Ugo Monye (Harlequins) Mathew Tait (Sale Sharks) Mike Tindall (Gloucester) Jonny Wilkinson (Toulon) Injured Delon Armitage (London Irish) Harry Ellis (Leicester) Toby Flood (Leicester) Riki Flutey (Brive) Olly Morgan (Gloucester) England Saxons Available Nick Abendanon (Bath) Brad Barritt (Saracens) Ben Foden (Northampton) Shane Geraghty (Northampton) Stephen Myler (Northampton) Paul Sackey (London Wasps) Joe Simpson (Wasps) David Strettle (Harlequins) Dominic Waldouck (Wasps) Richard Wigglesworth (Sale) Micky Young (Newcastle Falcons) Injured Danny Cipriani (Wasps) Topsy Ojo (London Irish) Jordan Turner-Hall (Harlequins) Sam Vesty (Leicester)