At these talks in Istanbul, no-one needed name tags. Almost everyone was here in January 2011 when the most recent round of negotiations collapsed.

Almost 15 months later, negotiators returned to Istanbul keen to avoid running into some of their old problems.

The central issue which underlies the nuclear dispute between Iran and the West is the lack of trust between the two sides. For decades, Iran and the West have shared an overwhelming lack of faith in each other´s intentions.

This has made reaching an agreement over Iran´s nuclear ambitions extremely difficult.

Diplomats here believed that a small dinner party might help to chip away at some of this legacy of mistrust.

So, on the eve of the negotiations, the world powers´ chief negotiator Baroness Catherine Ashton dined at the Iranian consulate with her Iranian counterpart Saed Jalili (the two were joined by their respective deputies). We are told that the dinner party conversation touched on the role of women in politics.

Giant poster unveiled

The next day, at the start of negotiations in the Istanbul Conference Centre complex, the two chief negotiators gave each other their own by-now traditional greeting - a polite nod at a noticeably cautious and respectful distance.

For religious reasons, Saed Jalili cannot offer his hand to Lady Ashton - the EU´s foreign policy chief knows this and she appears to make every attempt to make sure that she sticks to a simple nod.

The delegations from the world powers stayed at the nearby Hilton hotel. Before they talks began they swapped handshakes in the lobby. Iran´s delegation stayed some distance away at the Iranian consulate.

It is not immediately obvious if the negotiators from the six powers were able to strike up a rapport with their Iranian counterparts. One diplomat from the six powers appeared to be wearing a watch with Persian numerals - but perhaps this was just a coincidence.

The day´s opening session lasted two-and-a-half hours and was described as positive. Bilateral meetings and a final plenary session continued into the evening. At one point there was a report that the US and Iran had decided to hold their own individual meeting (if true, this would have been the big news of the conference). Minutes later Iran´s state media denied the rumour.

Finally, just after 21:00 local time, Baroness Ashton took the escalators down to the nearby media centre to announce that the two sides had agreed to meet again in Baghdad next month.

"The talks have been constructive and useful," she told the news conference.

Lady Ashton took three or four questions and then left.

Shortly afterwards, Iran´s local diplomats approached the stage and prepared for the arrival of Saed Jalili. They unveiled a giant poster on the wall behind the podium.

"Nuclear energy for all, nuclear weapons for none," the poster read. It showed the pictures of a number of Iranian nuclear scientists who have been killed in the last two years. Iran accuses foreign intelligence services of carrying out the killings.

´Successful´

A few minutes later, Saed Jalili arrived at the media centre accompanied by his delegation - each wore an extremely smart suit and crisp shirt (Iran´s President Mahmoud Ahmadinejad may have pioneered a weather-beaten look, but Iran´s nuclear negotiators evidently like to be well-tailored.)

"In general what has happened today, because it was based on co- operation, it was very successful," Mr Jalili told the news conference. "If we carry on like this, there will be more success in the future."

Mr Jalili then remained on the podium to take well over a dozen questions. He showed little desire to leave.

In their respective statements, Lady Ashton and Saed Jalili announced that their deputies would hold framework talks before the next round of main talks in May in Baghdad.

These framework talks may turn out to be where specific offers are made and where Iran´s nuclear programme is discussed in detail.

Standing outside the main news conference room, almost entirely un- noticed by the Western press, was the man who will lead these talks for Iran - Ali Bagheri. Mr Bagheri gave interviews to a small number of Iranian state media reporters. The BBC briefly spoke to him as he headed for the escalators.

"Where will the framework talks be held?"

"I am just going up to discuss it," he said quietly as he stepped onto the escalator. "We have not yet agreed."

The escalator took him upstairs. (© BBC MMXII 04/15/12)