Voting has begun in Iran to elect a new President as Mahmoud Ahmadinajad is replaced after serving his maximum 8 years in charge. There are 6 candidates but Iran's Guardian Council has restricted those who can stand, banning women or other candidates with an agenda considered to be reformist or liberal.

There are no political parties in the conventional sense - just a contest between candidates who prefess absolute loyalty to the Supreme Leader the Ayatollah Ali Khamenei and others who are considered slighting more reformist but by no means moderate.

On the campaign trail, Iran's nuclear negotiator Saeed Jalili is seen as one of the front-runners.

He has positioned himself as the most hardline of the candidates but there is speculation he may be viewed by Iran's Supreme Leader as too much of a wild card because of his implaccable attitude to the west. His election would signal a no-change President in Iran's posture to the outside world.

Another favourite is Mohammad Ghalibaf, the current Mayor of Tehran, who is a conservative with strong ties to the security forces. If there is such a thing as a moderate voice amongst the conservative candidates it is Hassan Rouhani, a British-educated cleric.

On the streets of Tehran people who might count themselves amongst the opposition have been gathering to support him, because in the absense of a more reformist figure he may get their vote. But whoever wins will have a limited mandate on nuclear policy and relations with the West.

In Iran it is the hardline Supreme Leader who has the say, not the President.

Economy is big issue

The Supreme Leader spectacularly fell out with Mahmoud Ahmadinajad in spite of backing him in 2009 during elections which critics said were rigged and led to wide-spread protests.

A participant, want to be identified for fear of reprisals, in the demonstrations dubbed the 'Green Revolution' told us he he was held for 6 months and tortured.

He said "I was like an empty person, an animal. I was like a piece of meat. If there are demonstratons during this election - and I hope there will be - and people take to the streets in Tehran they must stay out day and night. And if people get killed, injured, arrested and tortured they must persist and stay out on the streets for the government to fall. They cannot go back to the roof tops and just shout slogans."

One of the biggest issues domestically is the economy, which is in its worst state for decades with high inflation, soaring unemployment and negative growth.

The value of Iran's currency, the rial, has more than halved in a year, after a collapse blamed on government mismanagement and sancitons against Iran's energy and banking sectors imposed by the US and EU.

The fall of the rial has led to sharp cuts in imports and raised Iran's inflation to its highest level in 18 years.