Iran’s president, Hassan Rouhani, has to weigh up every step he takes as he visits the UN in New York, accommodating world leaders while not upsetting hardliners at home.

Wednesday’s meeting with the British prime minister, David Cameron, the first such encounter in decades, just added to the complications.

In Tehran, domestic repercussions of any potential statements he will make or meetings he will attend, can be costly. Hawks and fundamentalists, such as those in the Iranian parliament, will be circling like vultures to watch him slip.

Last year in New York, the 65-year-old made a difficult choice and despite his own willingness decided not to commit to a historic handshake in the corridors of the UN headquarters with the US president, Barack Obama.

Instead, he opted for a less controversial, yet hugely significant, telephone conversation with the American leader. Still, he remembers well that he returned home to Tehran airport to protesters throwing eggs and shoes at him.

This time, the task is no less intricate. Rouhani has already met a number of world leaders, including France’s François Hollande and Austria’s Heinz Fischer. His meeting with Cameron marked a milestone as the first meeting between UK and Iranian leaders since the 1979 Islamic revolution.

In Iran, where suspicion is rife about Britain, that meeting will be watched closely with attention to the details.

Iranian hardliners have an extraordinary obsession with Britain (which they still consider “the old fox”) and approach it with a conspiratorial mindset. In their view, British hands are behind everything political in Tehran and the royal family still runs Westminster. Iranian conservatives have a suspicion towards Britain much deeper and stronger than towards the United States.

The British embassy in Tehran, which was shut down in 2011 following an attack by an angry mob, remains closed. Both sides have decided to reopen embassies but complications in Iran mean the UK mission is not fully open.

Iranians with dual British citizenship are also subject to scrutiny and a number of them are being held in jail, including Ghonceh Ghavami, a 25-year-old female University of London graduate who was arrested nearly three months ago for trying to enter sports stadiums with men.

Keyhan, an ultra-conservative Iranian newspaper whose director is appointed directly by the country’s supreme leader, Ayatollah Ali Khamenei, published an editorial on Wednesday cautioning Rouhani about his meetings with the world leaders and a potential agreement with the west over Tehran’s nuclear programme.

Under the headline “The unfinished war”, the piece reminds its readers that the US and “England” – as Britain is usually called in the Iranian press – supported Baghdad in the eight-year war between Iraq and Iran in the 80s and still imposes sanctions on Tehran.

“The world’s imperialist faction [a familiar reference to Britain and the US] is aiming to bring the powerful and revolutionary Iran to its knees,” the article said.

However, Sadeq Zibakalam, a Tehran University professor, writing in the reformist Shargh daily on Wednesday, called the Rouhani-Cameron meeting historic.

“We cannot escape from the reality that this is going to be, undoubtedly, a historic meeting. It will have significant implications,” he wrote, predicting that their talks would be focused on the nuclear negotiations as well as fully reopening the embassies.

In Zibakalam’s view, Rouhani’s meeting with Cameron will also pave the way for his potential meeting with Obama. “With a flower, you can’t have a full spring but when a flower blossoms it means an end to the winter season,” he said.

Rouhani, meeting a group of American journalists and editors in New York on Tuesday, also expressed hope for a permanent nuclear settlement between Tehran and the west.

“Without a doubt, reaching a final nuclear deal will expand our cooperation, and we can cooperate in various fields including restoring regional peace and stability and fighting against terrorism,” he said.

“I believe both sides have reached the conclusion that the continuation of the current condition doesn’t benefit anyone … So why not make strides to reach this agreement?”

Rouhani also said a nuclear agreement would bring further opportunities of cooperation between Iran and the west.

“If there is a serious will, we can reach a final agreement in the next two months,” he told US editors. “Our wish is to close this dossier forever.”