British Energy, the UK nuclear energy generator which has suffered a 9% fall in its share price in this year, is set to drop out of the FTSE 100 index of blue-chip companies next week, putting selling pressure on the stock from passive fund managers.

Shares in British Energy fell 24% in one day's trading on October 16, after the company said it would be closing two of its reactors. Its largest shareholder is Invesco with almost 15%.