In the Lock No 5 bar – a room in Twickenham’s east stand dedicated to second-rows – Steve Borthwick was conspicuous by his absence. English rugby’s power brokers had gathered to unveil the vaunted new agreement which will shape the landscape of the game but the national team head coach was nowhere to be seen. Perhaps he was busy trying to fill the gaps in his backroom staff.

The Professional Game Partnership (PGP) governs how club and country coexist, how the Rugby Football Union and Premiership Rugby cooperate. There was backslapping, talk of “landmark agreements” and “historic collaboration”, but pick through the bones of it and it is clear that whether it succeeds or fails rests almost entirely on Borthwick’s shoulders.

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Because, for all the bells and whistles of the PGP, for all that there has been much diligent work to admire on academy structures, pathway systems and a long overdue joint marketing agreement, the crux of these agreements will always be player access. How much of it the England head coach can get and how much the RFU has to reimburse clubs as a result.

The new deal dictates that Borthwick will pick a group of 50 players in an elite squad and he has licence to award up to 25 of them enhanced contracts. Crucially, Borthwick has more control over those on enhanced contracts and the most significant line in the PGP announcement states that he will have “the final say on all sports science and medical matters”. It is the one bit of the agreement that made you double‑take. A declaration of something more than was expected.

Whether it means Borthwick can dictate when players appear for their clubs – or more pertinently when they do not – is open to interpretation. Premiership coaches have expressed concern that while it does not explicitly, it effectively will, and the wording appears to go further than suggested recently by the Northampton director of rugby, Phil Dowson. In theory, any decision Borthwick makes that a player should be stood down can be attributed to sports science.

The RFU and Premiership argue that with each player having their own individual development plan (IDP) – a micromanaged programme for the season – the instances where conflict arises will be few, and as part of the agreement there will be an independent chair of the newly beefed up Professional Rugby Board to arbitrate. They will decide whether Borthwick is making a “reasonable” decision and there will be “checks and challenges”, according to the RFU’s Conor O’Shea.

“We have to enter this in really good faith,” the Premiership Rugby director, Phil Winstanley, said. “This is a conversation we have had multiple times with the directors of rugby. Steve has been speaking to the directors of rugby. The simple answer is Steve has the final say.”

The whole situation is nebulous, however. The RFU is paying the clubs £33m a year as part of the new deal, a sizeable uplift, and it will expect something significant in return. Borthwick was furious when Ollie Lawrence turned up before the Six Nations with an injury that Bath knew he had, but he did not, and he is determined to avoid a repeat.

It is the weeks before international windows that are likely to provoke most conflict; when a player needs an injection, or a breather, and England want him to take it before turning up to camp. Equally, it should not be forgotten that Sale warned England that taking Tom Curry on the summer tour of Japan and New Zealand would shorten his career and Borthwick picked him anyway, so we take with a pinch a salt the insistence that decisions will be made with the player at heart. “Ultimately someone has to have the final say,” O’Shea said.

It falls to Borthwick, but there remains much to iron out before the season starts because how many players he has control over is also unclear. O’Shea was insistent that Borthwick will not award all 25 contracts before the autumn on the basis that he wants their rarity to enhance their value in the players’ eyes.

There have, however, been concerns that the RFU cannot afford all 25 and negotiations with Team England Rugby – the organisation that now represents players in contract talks with the union – have not been finalised. Hurdles are still to be overcome, not least over player welfare, because the players are determined to avoid a scenario such as last season when Maro Itoje went over the game limit of 30 appearances.

Borthwick, to his credit, has done his best to assuage doubts that the clubs have, including the fact that he does not have any strength and conditioning coaches after the departures of Aled Walters and Felix Jones. He has been to see six clubs in pre-season and each coach seems far happier once he has been to visit. It is often said that the success of this deal will be determined by relationships and it is true that Borthwick has done much to rebuild bridges burned by Eddie Jones.

“We have to have better communication and relationships between the England head coach and the directors of rugby,” Winstanley said. “Steve’s put so much effort into this over the last few months and that’s started to play out in the success of this process.”

So much rests, then, on how Borthwick continues to manage those relationships, while exerting the control he wants. Tucked away in the corner of the Lock No 5 bar there is a plaque dedicated to Borthwick that has the words “pillar of strength” emblazoned across it. Certainly it is he who wields the power.