By Miranda Eeles BBC correspondent in Tehran

More than 100,000 students in Iran will be taking their final university exams in the next few weeks.

Bright Iranian youth are deserting in their thousands

But while they may be looking forward to finishing their studies, what comes afterwards is a different matter altogether.

A population boom in the 1980s means the country is now overwhelmingly young, with around 70% under the age of 30.

Faced with poor job prospects and restrictive social conditions, thousands are leaving every year, creating alarm among the country's leaders.

'Everyone wants to leave'

Ehsan Afshar is spending his last afternoon with his friends at a cafe in north Tehran.

For three years he has been trying to leave Iran. Finally his dream - a chance to study abroad - is about to come true.

After trying five different embassies, India came up trumps and he has a year at a university in Puna.

"Everyone wants to leave because of the economic problems, because of the social conditions facing young people," he said.

Many young people have lost patience with the slow pace of reform

"They don't understand what going on. In a way, young people just see walls in front of them, a kind of obstacle.

"It's really bad at the moment, really bad."

Iran's universities are full of students like Ehsan. Out of more than 1.5 million undergraduates, many face an uncertain future when they leave. The jobs are simply not there.

It is not only the prospect of unemployment that is forcing them to look overseas.

These are children born after the Islamic revolution. They want freedom that they feel the government is not prepared to give them.

Dr Hassan Hossein, a lecturer in sociology at Tehran University, said: "When someone goes to university, it means they have entered an intellectual environment; they read more, they notice things more.

"There's a direct correlation between how closed a society is and the likelihood of flight from that society."

English boom

English-language schools have mushroomed all over the country in the past few years.

Qeshm language school in central Tehran opened just under a year ago with 80 students.

The brain drain is a problem for the country because we are losing highly educated people and these people... could be our entrepreneurs who create jobs for the next generation Pooya Alaidini, economist

Now they have more than 500 on their books. In fact so huge is the demand for places, they have had to open two other schools, with two more on the way.

Most of the classes are for students preparing for an English-language exam, known as IELTS, compulsory for study overseas. Last year the number of applications in Iran rose by 84%.

Now hundreds of thousands are leaving every year.

Brain drain

Economist Pooya Alaidini says Iran is suffering from the loss of so much talent.

"The brain drain is a problem for the country because we are losing highly educated people and these people... could be our entrepreneurs who create jobs for the next generation."

The Iranian Government does actively export mainly manual labour to other countries.