International Power was the biggest riser at the close of trading after it revealed it had received a takeover bid from majority shareholder GDF Suez.
The bid for the remaining 30% of the shares that the French company does not already own is valued at 390p per share – approximately £6 billion.
The news lifted the FTSE 100-listed company’s share price by 5.6% to 405p.
Rio Tinto rose by 1.8% to 3,375.5p as Imperial Tobacco closed 1.5% higher to 2,557p. Asset manager Aberdeen increased by 0.5% to 258.1p, as Vodafone climbed 0.4% to 174.45p.
The biggest faller was Barclays, which saw its share price drop by 4.7% to 234.15p.
It was joined at the bottom by Aviva, down 3.4% to 325.1p, and engineer Weir, which closed 31% lower at 1,698p. Building supplies company CRH also dropped 3.1% to 1,250p, while Lloyds Banking Group slipped 2.9% to 33.42p.