Declining oil and gas production saw UK stocks fall for the third straight day.
This week’s slide could see UK stocks make their first loss in the past six weeks.
The FTSE100 Index fell 0.6%, sliding 38.02 points to 6,685.
OPEC’s decision to hold firm on output saw Tullow Oil and BG Group each lose 4% amid mounting anxiety the price of oil will continue to plummet.
The decision, which sent the social media sphere into a frenzy, will see the 30 million barrels of oil a day output remain.
The group, made-up of 12 major global producers, resisted calls from countries like Venezuela to shift targets in a bid to cushion the recent oil price blow.
Earlier this week, Saudi Arabia’s Oil Minister Ali Al-Nami hinted his country would lobby for no output change, insisting prices would eventually right themselves.