A Downing Street spokesperson said:
The Prime Minister spoke to President Hassan Rouhani of Iran by telephone earlier today.
President Rouhani congratulated the Prime Minister on taking office. They agreed that relations between our countries had developed positively since the nuclear deal and that we should continue to advance the relationship.
They discussed the progress that had been made on implementing the nuclear deal over the last year and agreed that all sides should continue to honour the commitments made. The Prime Minister underlined that the UK would continue to play an active role in support of full implementation of the deal, including efforts to enhance banking cooperation between the UK and Iran.
The Prime Minister raised concerns about a number of consular cases involving dual nationals, including that of Mrs Zaghari-Ratcliffe, and stressed the importance of resolving these cases as we worked to strengthen our diplomatic relationship.
Finally, they agreed on the importance of dialogue on regional challenges and the global fight against terrorism.