Iran's belated admission that it was responsible for shooting down Ukraine International Airlines (UIA) flight PS752 could ultimately pave the way for a fresh round of negotiations on the controversial issue of its nuclear programme. Pictured: Part of the wing of the downed UIA airliner, near Tehran, Iran on January 8, 2020. (Photo by Akbar Tavakoli/IRNA/AFP via Getty Images)
Iran's belated admission that it was, after all, responsible for shooting down Ukraine International Airlines flight PS752, killing all 176 people on board, could ultimately pave the way for a fresh round of negotiations on the controversial issue of its nuclear programme.
The fact that Tehran has now been forced to admit that the Ukrainian aircraft was shot down by an Iranian anti-aircraft missile, and that the disaster was not the result, as Iranian aviation experts had initially claimed, of a catastrophic engine failure, represents a major setback for the regime's hardliners, who have ultimate authority over the country's military.
It was the hardliners, who take their orders directly from the country's Supreme Leader, Ayatollah Ali Khamenei, who have been responsible for the recent escalation in tensions between Iran and the US by encouraging Iranian-backed militias in Iraq to carry out the missile attack on a US base near Kirkuk that killed an American contractor, and the subsequent attempt to storm the American Embassy in Baghdad.
It was these attacks that prompted Donald Trump to authorise the assassination of Qasem Soleimani, Iran's master terrorist, which in turn resulted in the Iranians shooting down the Ukrainian aircraft after they mistook it for a US cruise missile.
Consequently many Iranians are blaming the country's hardliners for creating the circumstances in which the country has suffered arguably its greatest national humiliation since its 1979 Islamic Revolution, with the result that the hardline factions that support Mr Khamenei are now very much on the defensive.
This had led Western diplomats to conclude that this might present an opportunity to reopen negotiations on the 2015 nuclear deal with Iran that Mr Trump has denounced as being "flawed".
Prior to the Ukrainian aircraft disaster, such a prospect appeared remote indeed as, far from being in a mood to compromise, Iran had signalled that it was resuming work on its enrichment programme, a clear breach of the nuclear agreement.
The Iranian move was initiated by the hardliners, who have always been sceptical about the deal negotiated by the country's moderate foreign minister, Mohammad Javad Zarif, and they took advantage of the international outcry generated by Soleimani's assassination to downgrade Tehran's compliance with the agreement.
Now the tables have been turned in the wake of the Ukrainian aircraft disaster, to the extent that the hardliners are very much on the defensive, with moderate political leaders accusing the hardliners of misleading the government over the circumstances relating to the downing of the aircraft. President Hassan Rouhani has aligned himself with the moderates by demanding a thorough and transparent investigation in the "unforgivable error" committed by the Islamic Revolutionary Guard Corps (IRGC), which has been blamed for shooting down the aircraft.
This outcome had led Western diplomats on both sides of the Atlantic to conclude that, with the moderates once more in the ascendancy in Tehran, there is an opportunity to renegotiate the nuclear deal.
This is certainly the view of British Prime Minister Boris Johnson, who has called for the deal previously negotiated by US President Barack Obama to be replaced with what he calls a "Trump deal".
Speaking in his first interview since his impressive victory in last month's general election, Mr Johnson said he recognised US concerns about the 2015 deal, but insisted there had to be a way of stopping Tehran from acquiring nuclear weapons.
"If we are going to get rid (of the 2015 deal), we need a replacement," he told the BBC. "Let's replace it with the Trump deal."
Mr Johnson's comments came shortly after the three European signatories to the deal -- Britain, France and Germany -- announced that they were triggering a dispute mechanism in the deal following Iran's recent violations of the deal.
Which means that Tehran now faces a stark choice: either it reenters negotiations and addresses the serious flaws in the deal agreed by Mr Obama, or it faces yet further international isolation.
Con Coughlin is the Telegraph's Defence and Foreign Affairs Editor and a Distinguished Senior Fellow at Gatestone Institute.