Short for Säkerhetspolisen, SÄPO is the Swedish security service. Their main task is to protect the form of government. This is a big subject that covers a large variety of threats; everything from protecting against coups d'état to counter-espionage to counter-terrorism. SÄPO's areas of responsibility can be summed up into four main areas; counter-espionage, constitutional protection, counter-terrorism and personal protection.
The objective of the counter-espionage is to prevent and discover espionage and other illegal intelligence activity against Sweden. The major part of the efforts in counter-espionage is used to prevent espionage aimed at the Swedish defence forces. Though industrial espionage can be considered a threat to the nation, SÄPO is only concerned when it falls under the legal definition of espionage, i.e. when the espionage aims at acquiring industrial secrets of interest to the military. The counter-espionage is the task that most people associate with SÄPO, mainly because of a number of a number of cases who have attracted much attention from the media. The most well known case is that of Soviet spy Stig Bergling, who was convicted to lifetime imprisonment but later fled in a, to the police, most embarrassing way.
While the counter-espionage serves to protect Sweden from threats from the outside, the constitutional protection serves to protect from threats from the inside. (Domestic terrorism) This means protection against groups who aim to change the form of government or achieve other "large" goals with non-democratic methods. The organisations that SÄPO seems to most interested in are neo-nazi, militant vegan and different more or less revolutionary left wing groups.
The counter-terrorism branch aims to prevent terrorism with international political motives. The goal is to, with the help of intelligence, to stop the terrorists before they strike. Preferably by denying potential troublemakers entry into the country.
The personal protection division serves to protect the lives of important governmental persons, mainly members of the cabinet and the royal family, but also those of foreign dignitaries visiting Sweden. The personal protection division haven't got a very good reputation thanks to many embarrassing events. For example, in the summer of 2001 a 15-year old boy managed to throw a cake (strawberry flavoured) in the King's face without any intervention from the bodyguards before the attack.
SÄPO serves under the Swedish national police board. SÄPO's board contains representatives from both the police and the Riksdag (the Swedish parliament). As insight from the public and media into SÄPO's business is strongly limited, their activities are checked by the Attorney General and the parliamentary ombudsman. A special committee, the registry committee, checks SÄPO's registration of personal particulars.
The SÄPO headquarters are located in Stockholm and they have offices in all of the other twenty police districts. Their yearly budget is about 500 million SEK.
These days, SÄPO have their own home page. It can be found at http://www.securityservice.se. Beware, the site is entirely in Swedish.
Sources:
Nationalencyklopedin
The Swedish Police - http://www.police.se