David Cameron writes to Iran’s new president in attempt to mend relations

The British prime minister, David Cameron, has reached out to Iran's new president, Hassan Rouhani, expressing hope that his election will create an opportunity for an improvement in long-strained ties between London and Tehran.

Cameron's letter was sent to mark Rouhani's inauguration on Sunday, according to Downing Street, when the new president took his oath of office in the Iranian parliament in front of foreign dignitaries and senior Iranian politicians.

"I wanted to write to express the hope that your election will present an opportunity to improve relations between our countries," Cameron wrote in his letter.

Britain has not had a diplomatic presence in Iran since November 2011 when its embassy in Tehran was stormed by a mob, triggering one of the worst crises between the two countries since the 1979 Islamic revolution. London and Tehran's bilateral ties have since been downgraded but not fully severed.

Cameron's missive was unusual given the poor relations between Iran and the UK under Rouhani's predecessor, Mahmoud Ahmadinejad, and given the Foreign Office's recent snub to Tehran's invitation to attend Rouhani's swearing-in ceremony, which was criticised by the Labour party as a "missed opportunity". Rouhani's victory in the Iranian election has raised hopes for better relations between Tehran and the international community, especially the US.

Cameron said he hoped Tehran would take a different course in the future and be prepared to improve London-Tehran ties on a step-by-step and reciprocal basis, according to No 10.

"Improving bilateral relations will be a gradual process and several issues will need to be addressed," he wrote.

The prime minister also urged the new Iranian administration to "engage constructively and seriously" with the international community to address its concerns about Tehran's disputed nuclear activities.

Nuclear talks between Iran and the world's major powers – the US, France, Germany, China, Russia and Britain, the group known as P5+1 – have reached stalemate but Rouhani said at his first press conference in Tehran on Tuesday that his government is determined to negotiate "seriously" in order to resolve the issue in short time.

Cameron has also asked Rouhani to support a peaceful resolution to the Syrian conflict. Rouhani said this week that his government would be against foreign intervention in Syria and that its fate should be decided by its own people through election and democracy.

The British foreign secretary, William Hague, made similar remarks last week when he called his Iranian counterpart, saying that the UK is open to improving London-Tehran ties on "a step-by-step and reciprocal basis". Hague told the outgoing Iranian foreign minister, Ali Akbar Salehi, he will be willing to meet his new Iranian counterpart in New York in September at the time of the UN general assembly.

Rouhani has nominated Mohammad Javad Zarif, an Iranian former ambassador to the UN, as his foreign minister but his ministerial appointment will only become official if he passes a confidence vote in the Iranian parliament next week. Zarif has told Iranian MPs that normalising Tehran's ties with the EU and managing its relations with the US would be among his priorities in office, the semi-official Mehr news agency reported.