* FTSE down 1.5 pct at close
* GKN eyes sale of auto unit(Recasts, adds detail, quote and updates prices at close)
By Julien Ponthus and Kit Rees
At its close, the FTSE was down 1.5 percent at 7,069.90points at its lowest since December 2016, unnerved by PresidentDonald Trump's promise to tax aluminium and steel imports.
While initial reaction to May's speech was muted, both theblue chip FTSE 100 and sterling drifted lower as it ended withthe prim minister saying "no deal is still better than a baddeal in Brexit talks".
"There wasn’t much for traders to latch on to," said DavidMadden, market analyst at CMC Markets
The FTSE usually rises when sterling falls owing to theFTSE's high proportion of internationally-exposed firms, whichbenefit from a weaker local currency.
Shares in miners Rio Tinto and BHP Billiton,which have large iron ore exposure, were more than 3 percentlower and among the biggest FTSE 100 fallers.
Rentokil rebounded after falling during the previoussession on disappointing 2017 results. The British businessservices group gained 3.6 percent.
Paper and packaging firm Mondi was the biggestgainer, up nearly 4 percent after announcing a special dividendafter resuming profit growth.
London Stock Exchange Group fell 2.7 percent afterreporting its 2017 results as traders noted higher costs.
British engineering company GKN was down 3.5percent. It said it was in talks with Dana Incorporatedover its auto unit, opening up a new front in an attempt tofight off a hostile 7 billion pound (
