He belongs to the 1968 batch of the Kerala cadre and retired as chief of the Intelligence Bureau in January 2005.

Mr. Doval, who belongs to Garhwal, has outstanding credentials as an operations man. He made his name as a field operative in the Mizoram insurgency where he broke rebel leader Ladenga's hold over his private army. In 1989, he lead an IB team along with the Punjab police and National Security Guards in Operation Black Thunder to evacuate terrorists from the Golden Temple in Amritsar.

For many years he led many important teams within IB which included the important operations against Islamic terrorism in India. He also led the team set up to capture underworld gangster Dawood Ibrahim after the Mumbai bomb blasts in 1993.

He has also served in Pakistan when J N Dixit was India's High Commissioner.

He was also one the three negotiators along with diplomat Vivek Katju and C D Sahay, intelligence officer of the Research and Analysis Wing, to negotiate the release the passengers of IC 184 flight that was hijacked to Khandhar.

Few men in the IPS know India's internal security problems as well as Doval.

What are the challenges before India on matters related to internal security?

In the last decade a series of studies have been carried out in India and abroad to figure out what exactly are India's security vulnerabilities. All studies agree on one point -- that India's internal vulnerabilities are much higher than its external vulnerabilities. You read the report of the Group of Ministers Task force, the report of the National Security Advisory Board or the US State Department's assessments -- all say internal security vulnerability is at 75 to 80 percent.

In the global context, after World War II very few countries have lost their territory, their constitution, their economy because of external factors. East Timor, Bangladesh and the breaking up of the Soviet Union was because of internal factors that lead to civil war or breakdown of law. India is an old civilization which is converting into a new nation state. This is highly exothermic. This heat is necessary because this leads to amalgamation.

But the process makes fault lines fluid. India has got all the fault lines -- ethnic, religious, cultural, linguistic and caste. The synthesis is on but there has yet to be amalgamation. The transition is a difficult phase. I expect that in 2050, due to education, the economy and development the fault lines will vanish. India's internal vulnerability is also because of political factors.

Political leaders' fortunes lie in exploiting these fault lines. While all political leaders want to strengthen national unity, their future lies in exploiting the fault lines. Here lie the contradictions. To get the vote of a particular community I'll need to accentuate their favours. If the minority or majority are not afraid of each other then there is no vote-bank. So politicians have to give voters an imaginary or real perception of fear. The genius of politics lies in exploitation of fears and invention of new ones.

But there are very positive, competent and determined people inside and outside government who will bridge these fault lines.

This is the broader picture but can you tell us how you see the micro issues? Which is the most prominent issue threatening India's internal security?

I consider infiltration of Bangladeshis the biggest internal security problem. It's the biggest because the government feels that it can do nothing about it. There is no military response, diplomatic responses have failed, border management is not effective and the legal response is not doable because two crore illegal people's adjudication will take 200 years. Even then, you can take those adjudicated outsiders to the border, Bangladesh may not accept them. And even when they are accepted they come back after 15 days to a new destination in India. When an Indian court convicts somebody as a Bangladeshi his government escort buys him a ticket, gives him food and takes him to the border. But in a large number of cases the Bangladesh Rifles refuse to accept India's evidence. Bangladeshis enjoy a paid holiday in this country!

Even if he is accepted, by paying touts around Rs 3,000 in Dhaka he can get back on a border-bound bus.