India-Pakistan, that old, festering wound, is potentially holding hostage cricket's attempts to devise a new international calendar, as the PCB has made it clear it will not sign up without clarity on bilateral matches with India.

The ICC is optimistic that a new calendar, designed to bring context and meaning to international cricket, will be presented to its board for approval at a meeting in Auckland in October. That calendar will have the top nine sides play a two-year Test league with a play-off at the end, and a 13-team, two-year ODI league that is a qualifier for the World Cup.

At a scheduling workshop in Dubai last month, board chief executives from around the world gathered to finalise details of the new structure. Though the meeting was seen as the final step to a process in the works for over a year, the PCB posed a late hurdle.

The Pakistan board agrees with the new structure, and has even largely worked out its commitments within it. But the ICC was told clearly that if the BCCI did not agree to ink in bilateral commitments outside the league windows, the PCB will not sign off on it in Auckland. The calendar includes an eight-month window during which members are free to schedule bilateral ODI series of their choosing. Whether the PCB's threat can actually derail a revamp - and the impact it has on any vote - is not yet clear.

The PCB has reluctantly agreed to the BCCI's request to not schedule any Tests or ODIs against India within the league structure. That will avoid instances such as last November, when the Indian women's team forfeited points for not playing a three-match series with Pakistan. It dilutes the idea of a league in which each side is required to play six series (and not everyone) over two years. And it isn't clear what happens if India and Pakistan meet in the final play-off.

But in return, the PCB wants some commitment from India that they will play, or at least ink in a commitment, in that eight-month window. That, a PCB official said, was crucial: "If you are not going to list that series it means we are not playing India for the next eight to ten years and we are not in a position to take that risk, to go to the next broadcast rights and say there is no India. For us, it's a decision worth US $130 million.

"We said to other boards there, will any of you agree to a schedule without India? Will Australia do it? England? If you can't, why should we? Our position is that this is non-negotiable. This whole structure becomes viable if, outside the structure, we have India scheduled. If that doesn't happen, then we won't be able to sign this."

India and Pakistan have not played a full bilateral series since late 2007. The terror attacks in Mumbai the following year resulted in a sharp deterioration in diplomatic ties between the two countries; in that time, they have played one bilateral series, a short, limited-overs series in India. The PCB has sought repeatedly to restart ties, but the BCCI insists it cannot until the Indian government green-lights it.

Complicating matters is an escalation of the PCB's ongoing efforts to resolve the issue of already-cancelled series with India from the current calendar. In May this year, the PCB sent a notice of dispute to the BCCI for not fulfilling obligations of an MoU agreed upon in 2014 for six bilateral series between 2015 and 2023. The first of those - in December 2015 - never went ahead; another is scheduled for 2019.

As per the ICC's code for disputes, the two sides met a few times to attempt a breakthrough. But with little progress, matters became heated at the last meeting in London in June, during the ICC's annual conference. Now the PCB is on the verge of sending an official notice of dispute to the ICC.

The ICC chairman Shashank Manohar sat in on that meeting as the arbitrator, or facilitator, between the two boards. Manohar had dealt with the issue first hand during stints as BCCI president before he moved to the ICC. In London he told the PCB in no uncertain terms that pursuing a legal route would mean ending any hopes of ties with BCCI. Instead he urged more patience. But where Manohar felt he was spelling out the reality to the PCB, the Pakistan board felt he was representing a BCCI view, adopting a partiality at odds with his ICC role.

The upshot is that the PCB is due to meet with lawyers in the UK, before sending the official notice of dispute to the ICC. That is part of a distinctly harder line adopted by the recently appointed PCB chairman Najam Sethi as compared to predecessor Shaharyar Khan, a former diplomat more open to discussion than direct confrontation.

"What is the harm in pursuing this legal option?" one PCB official explained. "At most, we will lose [and not play]. If government ties get better, then in any case the BCCI can't stop from playing us."

The basis of the PCB's legal argument rests on whether the Indian government has explicitly - and in writing - denied the BCCI permission to play against Pakistan. Ordinarily, the protocol for India to tour anywhere is that the BCCI writes to the Indian Sports Ministry, and copies in the Home Ministry and External Affairs Ministry seeking permission. Usually the Sports Ministry responds granting approval.

In the case of Pakistan, however, approval must come from all three ministries and especially the Home and External Affairs wings. The last time BCCI approached the Indian government for permission for a Pakistan series was last year, but there was no response.

The PCB is seizing upon this, pointing to a decision the British government took in 2008 to cancel a tour of the country by Zimbabwe in 2009 on political grounds. Then, the government sent a letter to the ECB instructing it to cancel.

"We said have you [BCCI] ever got a no from them [Indian government]?" the PCB official said. "They said no. We said have you ever written to the government? They said yes. We said why have you assumed it is a no? It is your assumption. If you don't get a response, it is your assumption."

In case the BCCI now produces a government letter, the PCB' will still argue that their grievances date back to previously cancelled tours, for which there are no letters.

The BCCI position, a board official said, was clear and had been reiterated to the PCB. "No matter how much noise they make this is a decision of the Indian Prime Minister's office. And so there is no point discussing or arguing. The PCB ask us to play and we (BCCI) respond that this is way above us. This is a government decision. The BCCI does not have the authority to commit."

The sides continue to play each other in ICC events, most recently twice at the Champions Trophy earlier this year. India won the first game in the group stages, but Pakistan surged to an upset win over them in the final.

Last week, the ICC chief executive David Richardson said the ICC's role would be to facilitate and let the dispute process "take its course".