When a private Qatari jet carrying five Iranian-US nationals touched down in Doha, US president Joe Biden was finally able to claim a success after months of secretive, high-stakes talks between Washington and Tehran.

The five dual nationals had been imprisoned for years in the Islamic republic — some on accusations of spying for the US — and were finally freed and flown out of Tehran on Monday after the two arch enemies agreed to a complex prisoner exchange. Under terms of the deal, Washington released five Iranians held in the US and allowed Tehran to access $6bn of its oil money previously frozen in South Korea.

The critical question now is whether Washington and Tehran are able to build on the prisoner swap and use it as a foundation to seriously address Iran’s aggressive nuclear programme — arguably the gravest threat to Middle East stability.