New Delhi, April 15: The Indian foreign office today suspended the diplomatic passport liquor baron Vijay Mallya had used to fly to London last month, and threatened to revoke his regular passport too within a week, after his refusal to appear before the Enforcement Directorate (ED) in a loan default case.

Mallya flew out on March 2, a day after signing in his attendance in the Rajya Sabha, where his current term as an Independent MP from Karnataka ends in June. MPs are entitled to diplomatic passports if they apply for them. Mallya's latest entry into the Rajya Sabha had been facilitated by the votes of BJP and JDS members.

A consortium of banks has accused him of not repaying loans totalling to Rs 9,000 crore. The ED has issued three summons to Mallya under the Prevention of Money Laundering Act, but he has not responded to any of the missives, officials said. The directorate today requested a Mumbai court dealing with money-laundering cases to issue a non-bailable warrant against Mallya.

The suspension of the diplomatic passport, currently for four weeks, does not mean Mallya's stay in the UK or any other country he may have travelled to from London is automatically illegal.

In the UK, Mallya has held a residency card for the past 28 years that remains unaffected by the status of his passport. In any other country, too, his stay would become illegal only once his diplomatic passport is revoked, if that was the legal document he used to get into that country - since it would no longer be valid. But he can't travel on the diplomatic passport while it is suspended.

If both Mallya's diplomatic passport and his regular passport are revoked, he will no longer be able to legally travel anywhere or stay legally abroad in any country other than the UK. Till then, Mallya could use his regular passport to travel anywhere if he gets a valid visa - or has one already - from the country he is visiting. But Indian law enforcement agencies don't expect him to travel from the UK - his residence card there gives him a shield against deportation even if both his passports are revoked, an advantage he will not enjoy elsewhere.

"Mr Mallya has been asked to respond within one week as to why his passport should not be impounded or revoked," foreign ministry spokesperson Vikas Swarup said this evening. "If he fails to respond within the stipulated time, it will be assumed that he has no response to offer and the ministry of external affairs will go ahead with the revocation."

Every MP is entitled to a diplomatic passport under Parliament rules, and only needs to apply for the document. But Mallya has already violated a norm - though not a law with punishments - on the use of diplomatic passports.

All diplomatic passport holders are expected to hold regular passports too. They are expected to use their diplomatic passports only when travelling on official work where they are representing the government of India - the reason they have the special passport in the first place. For travel unrelated to work on behalf of the government of India - for a holiday, for instance - they are expected to use their regular passports.

But the implementation of this norm is complicated, ironically, by agreements the government has struck with over 60 countries that exempt users of diplomatic passports from needing visas for travel to those nations.

The idea behind these agreements was to smoothen official travel to countries that Indian diplomats and other official representatives are expected to visit frequently. But the absence of the need for a visa has meant even career diplomats often use their diplomatic passports for personal travel to the countries on this list.

It is harder to use a diplomatic passport for non-official travel to a country India does not have such agreements with. Such countries need to issue "official visas" for diplomats to travel on diplomatic passports. Such visas need official justification - a formal meeting, summit or at least a conference. India does not have an "exemption" pact with the UK - it is Mallya's residency card that allowed him to get into the country without a visa.