Britain will be hoping for smoother business ties with Libya after the release of convicted Lockerbie bomber Abdel Basset al-Megrahi.
The north African country was off-limits for decades and British and other oil firms agreed tough terms when they were at last able to sign exploration and production deals there.
Following is a list of some of the biggest foreign oil companies in Libya. Information is taken from previous Reuters stories.
BP - The British firm ended a 30-year absence from Libya in 2007 when it signed its biggest-ever exploration commitment through a bilateral deal. It will spend at least $900 million to search the onshore Ghadames area and offshore Sirte basin with 17 exploration wells.
Royal Dutch Shell - The London-listed company was awarded a gas exploration permit in 2007 for areas in the Sirte Basin, and was also awarded permits in 2005.
ExxonMobil - In February 2008 the U.S. oil major agreed with Libya's national oil company to invest $97 million plus tens of millions in fees in offshore hydrocarbon exploration. The company in 2005 struck an exploration and production-sharing deal with Libya's state oil company that covers the Cyrenaica Basin, covering 2.5 million acres, from deep to shallow waters.
Verenex - The Canadian company is the only winner of post-sanctions licenses under Libya's EPSA-IV tender mechanism to have made sizeable finds, prompting a battle for ownership of the company between Libya and China National Petroleum Corp.
Occidental - The company, which began business in Libya in 1966, reported first-quarter 2009 net production from Libya of 8,000 barrels per day, down from 22,000 bpd a year earlier. In late 2007 it won gas-focused permits to explore areas of the Sirte basin, and in 2005 was the biggest winner in Libya's first licensing round.
PGNiG -Libya's state-owned oil corporation ratified a gas exploration agreement in February 2008 with the Polish gas monopoly for to drilling at least eight wells at a cost of $108 million in the Murzuq Basin.
Gazprom - The Russian company was awarded a gas exploration license in 2007 for areas in the Ghadames Basin.
RWE - The German energy firm agreed to spend at least $76 million and drill two exploration wells in Syrenica basin blocks it won access to in late 2007.
Sonatrach - The Algerian state energy firm won blocks in the Ghadames Basin in December 2007.
Oasis Group - In December 2005 the consortium of ConocoPhillips, Amerada Hess and Marathon agreed to pay Libya $1.3 billion to extend their contracts in the Sirte Basin. The contracts were concluded before the sanctions were imposed, but the U.S. companies left Libya in 1986 after U.S. sanctions were imposed.
Nippon Oil - Japan's largest refiner in 2005 struck an offshore exploration and production-sharing agreement with Libya that also includes Mitsubishi Corp. and Japan Petroleum Exploration (JAPEX), which said it would invest $48 million in exploration over five years.
Petrobas - The Brazilian company was awarded licenses for exploring offshore in January 2005.
Following are some other companies with business ties with Libya, according to the British-Libyan Business Council:
BNP Paribas - Bought a 19 percent stake and strategic partnership in Sahara Bank for 145 million in 2007, the first partial privatization deal for Libya.
Barclays HSBC Standard Chartered J.P. Morgan Asset Management
(Compiled by Catherine Bosley)