LONDON, Nov. 21 (Xinhua) -- More than 850 British nationals are currently in overseas prisons for drug-related offences, said the Foreign Office on Thursday.

They are serving sentences from months to up to 39 years, it said.

"Some drug crimes can lead to even more severe penalties, and in 33 countries or territories some drug offences carry the death sentence," the Foreign Office warned.

"People continue to be astonished at some of the penalties handed down for certain crimes overseas," said Mark Simmonds, Foreign Office Minister for Consular Affairs.

In the last year alone, consular staff handled over 650 drug-related cases. "We want to reduce this number significantly," Simmonds said.

"Laws, penalties and sentences vary considerably around the world for the use, possession and trafficking of all types of drugs," he said.

He warned Britons not to take risks, saying "the consequences are simply not worth it."

The Foreign Office, in conjunction with the charity Prisoners Abroad, is launching a campaign to highlight the consequences of the use, possession and smuggling of drugs in countries around the world.

It also introduced penalties on drug-related offences in some countries such as Thailand, the United Arab Emirates, Peru and Indonesia.

Source: Xinhua, November 21, 2013