Update: Tobacco stocks have tumbled to the bottom of the FTSE 100 after The Wall Street Journal reported the US Food and Drug Administration was planning a ban on the sale of menthol cigarettes.
The Wall Street Journal report cited FDA senior officials, who claimed commissioner Scott Gottlieb was planning to pursue the ban, following a crackdown on e-cigarettes set to be unveiled this week.
It pointed to a 2013 FDA review that found menthol cigarettes harder to quiet than regular cigarettes.
US menthol cigarettes account for up to a quarter of British American Tobacco profits and under 5% of Imperial Brands' earnings, according to analysts at Deutsche Bank.
Tobacco stocks have long been a favourite of UK equity income fund managers.
Neil Woodford is among the sector's biggest backers, with Imperial Brands the largest holding in both his Woodford Equity Income and Woodford Income Focus funds. British American Tobacco is meanwhile a top 10 holding in the Woodford Income Focus fund.
British American Tobacco is meanwhile the second largest holding in the Invesco Income and High Income funds and Edinburgh (EDIN) investment trust run by Mark Barnett, Woodford's successor at Invesco, with Imperial brands also a top 10 position in the Edinburgh trust, down 1.6% at 637p.
The FTSE 100 meanwhile gained support from a falling pound, down more than a cent, or 0.8% against the dollar at $1.287 amid mounting doubts over prime minister Theresa May's ability to secure a Brexit deal.
The Independent reported May had been forced to abandon plans for an emergency cabinet meeting today to approve a deal, amid fresh opposition at home and abroad.
A weaker pound tends to support the FTSE 100, whose members rely on overseas markets for around three-quarters of their earnings.
Energy stocks rallied as the price of Brent crude lifted from lows, up 1.2% at $70.96 a barrel as top exporter Saudi Arabia announced a December cut in supply.
The more domestic-focused FTSE 250 was in the red, down 1.2%, but 'mid-cap' oil stocks bucked the falls.