The FTSE 100 has been dipping perilously in the past few weeks, giving up 722 points (10.5%) from its recent high of 6,905 on 4 September to Monday’s close of 6,183 — and if it can lose that much in three months it could certainly drop to 6,000 or lower by the end of December. Often such runs can be put down to individual sectors, and the big safe companies are there to offer some support and prevent a meltdown. But the crucial driver right now is oil. Brent crude crashed through the $60 per barrel level this week to reach its lowest since 2009, and as I write today it’s trading at a fraction under $59! Shell shares slumped by 17% between 21 November and close on 15 December.