Commodities stocks got a solid boost from Yellen's dovish stance which sent the dollar lower. A lower dollar led to an uptick in the price of Brent during London trading hours. However in later trade, the EIA announced that U.S. crude stockpiles had risen by 2.3 million barrels in the last week. Oil prices came off session highs in later trade, with Brent up over 1 percent, at $39.77, while US crude rose to $38.87.
Despite this, the solid gains pushed the likes of BP and Royal Dutch Shell sharply higher. Engineering firm Subsea 7 led the sector, closing up 6.7 percent.
"The good aspect of Yellen yesterday is the dollar. Dollar going down is clearly good for global growth, it's good for commodities, and it's good for emerging markets where the growing consumers are…that could pull the global growth up," Bruno Verstraete, partner at Lakefield Partners, told CNBC Wednesday.
And a number of miners also got a boost, supported by a positive outlook from brokers on some stocks and an increase in many metal prices. Anglo American jumped almost 12 percent and Glencore closed over 5 percent up after Jefferies raised its price target for the stocks. Basic Resources saw the biggest gains as a sector, closing 4.6 percent higher overall.