After years of unsuccessful lobbying by the Egyptian authorities for a reconciliation of the warring Palestinian factions, the post-Mubarak government has achieved a breakthrough. As Moussa Abu Marzouk, deputy head of the Hamas politburo, said on Thursday, a new page has been turned.

The emergence of a reconciliation deal between Hamas and Fatah on Wednesday took most observers by surprise, but behind the scenes a new cast of players had been moving the relevant pieces into place ever since a popular revolution ousted the Egyptian president Hosni Mubarak.

His regime had long declared publicly that Palestinian unity was a key foreign policy objective, and the rhetoric made sense. Hamas was proving a troubling neighbour in the Gaza Strip on Egypt's north-eastern border and Cairo had every interest in locking the political Islamists down into a more moderate political framework. Moreover, Egypt's stewardship of the negotiations boosted its flagging regional status and helped to ensure US political support – and money – kept flowing towards Cairo.

Egypt's hated spymaster Omar Suleiman was placed in charge of the unity drive, but below the surface Egypt was more interested in the appearance of reconciliation talks than it was in the reality. Israel and Washington had no genuine desire to see a unified Palestinian government, and Egypt's thinking followed suit – until, that is, nationwide protests erupted against the regime in late January, and Suleiman was promoted to vice-president in a failed attempt to shore up Mubarak's position.

Given the country's internal chaos, few expected his replacement, Murad Muwafi, to devote much energy to the issue of Palestinian factionalism, but in fact Muwafi took the issue seriously – so seriously, in fact, that no fewer than five Israeli delegations were dispatched to his offices in the space of a few weeks in an effort to ward off any unity deal.

Muwafi's stance was shaped partly by the ascendancy of the career diplomat Nabil el-Arabi to the position of foreign minister in Egypt's interim government. Arabi had a reputation for saying some decidedly undiplomatic things regarding Egypt's close alliance with Israel under presidents Mubarak and Sadat, and as part of an internal battle to wrest control of some policy issues away from the secret services – where they had drifted under Mubarak – and back under the auspices of the foreign ministry, he began making loud and relatively critical noises about Israel, marking an important shift in rhetoric. "It is time to stop managing the [Israeli-Palestinian] conflict, it's time to end the conflict," he said earlier this month.

Egypt, in short, was now ready to take Palestinian reconciliation seriously, and that shift in mindset coincided with further regional turmoil: the uprising in Damascus, where most of Hamas's leadership is based. With the long-term future of their host – Syria's president, Bashar al-Assad – in doubt, the group's top brass knew it could not risk alienating the Egyptians at the very moment Cairo was finally mounting a genuine push to bring Hamas and Fatah together.

Ahmed Moussa, head of the political section at the Palestinian embassy in Cairo, told the Guardian: "Our assessment is that if Hamas did not respond positively [to the latest Egyptian initiative] that would have had a very negative impact on their relations with the Egyptian authorities, and Hamas had to keep this consideration in mind, especially because of the problems within the Syrian regime."

With pro-reconciliation demonstrations bringing thousands to the streets of Gaza and the West Bank in mid-March, and a fresh push on the ground to reanimate the long-dysfunctional Palestinian National Council as a forum of national unification, the political climate was pushing both factions in one direction – and this week's announcement is the result.

Egypt's foreign minister will now travel to Amman and Ramallah next month to continue promoting the deal and, although few will admit it publicly, both Hamas and Fatah are optimistic that the new Egyptian government will do a better job of resisting Israeli pressure to scupper the agreement than Suleiman and Mubarak would have managed.