SINGAPORE, Nov 26 — A director-general at the Ministry of Foreign Affairs (MFA) was charged on Thursday over his alleged misuse of diplomatic bags.

Gilbert Oh Hin Kwan, 44, had allegedly used the diplomatic bags to send Panadol and luxury watches to China and back to Singapore.

TODAY explains what a diplomatic bag service is and how governments use them internationally.

What is a diplomatic bag service?

A diplomatic bag is used by foreign ministries to convey official correspondence and other items to and from the ministry and its overseas offices. These bags are usually sent by air without a courier though occasionally couriers are used.

Under international law — the Vienna Convention on Diplomatic Relations in 1961 — such bags are protected by diplomatic immunity and cannot be searched, seized or opened by customs.

This is also enshrined in Singapore’s Diplomatic and Consular Relations Act 2005.

The Act states that diplomatic bags must “bear visible external marks of their character” and should “only contain diplomatic documents or articles intended for official use”.

While there is no international standard on the size of a diplomatic bag, some countries have set limits.

China, for example, limits a diplomatic bag to be no more than 100cm in length, breadth or height. It also restricts the weight of each batch of diplomatic bags to not more than 100kg, according to its protocol guidelines for diplomatic missions.

These bags are sometimes transported by a diplomatic courier, who is also protected by personal inviolability and cannot be arrested or detained.

But while these bags cannot be searched, seized or opened, non-invasive checks on diplomatic bags have been performed by some countries.

The New York Times reported in 1988 that the United States Customs Service routinely used dogs to sniff-search baggage without separating parcels marked “diplomatic” from others.

Then-Second Minister for Home Affairs S. Iswaran told Parliament in 2015 that although the personal baggage of diplomats is generally exempt from inspection, such baggage will be inspected if there are serious grounds for believing there are prohibited or controlled items inside in Singapore.

He said this in response to Non-Constituency Member of Parliament Gerald Giam, who asked if the police were aware a diplomat was caught carrying up to 27kg of gold bars in his luggage after taking a flight out of Changi Airport.

How did these bags gain diplomatic immunity?

Even if a country suspects that a diplomatic bag service is being abused, the Vienna Convention on Diplomatic Relations does not provide any powers for that country to open or inspect the bag.

Prior to the convention, the accepted international norm was that a receiving state could challenge the contents of a diplomatic bag when it believed that the service may have been abused.

The sending state would then have the bag returned or allow it to be examined by authorities of the receiving state in the presence of a member of its mission.

However, in 1953, the United Nations requested the International Law Commission to look into codifying diplomatic interactions and immunities into international law.

In the debate leading up to the passing of the Vienna Convention on Diplomatic Relations, some delegates suggested diplomatic bags should be checked.

There were also proposals for a receiving state to reject a diplomatic bag should the country suspect the bag service to have been misused, but they were rejected.

“Ultimately it was decided that although there was a duty on the sending state to use the bag only for diplomatic documents or articles for official use, the bag could not be opened or detained under any circumstances,” wrote Professor of International Law Eileen Denza, a Briton, in a paper about the convention.

Denza added: “Given the purposes of diplomatic missions, secure communication for information and instructions is probably the most essential of all immunities.”

Have diplomatic bag privileges been abused?

Over the years, diplomatic bags have reportedly been used for smuggling various items, such as gold, weapons, drugs, and in some cases, even humans.

In 1984, a team of Nigerians and Israelis attempted to kidnap and repatriate a former Nigerian minister who had fled to England after a military coup.

British broadcaster BBC reported in 2012 that the kidnappers had drugged Mr Umaru Dikko, before putting him in a crate that they asserted was a diplomatic bag to be shipped to Nigeria.

He was discovered only when British customs officers received a notice of a missing Nigerian and opened the box in the presence of a Nigerian diplomat.

Diplomatic relations between Britain and Nigeria broke down for two years following the incident, according to the BBC.

In 2012, Italian police discovered 40kg of cocaine being smuggled into Italy through Ecuador’s diplomatic bag.

Five people were arrested for the smuggling case, and Ecuador claims it had inspected the shipment for drugs before it was sent to Italy. — TODAY