The FTSE 100 rose 102.3 points, or 1.7%, to 6,156.32. Rising prices of metals lifted mining shares, and Anglo American climbed 3.6%.
The biggest riser on the index was Coca-Cola HBC, which was 6.5% higher after Citigroup upgraded its rating on the stock to "buy".
In the FTSE 250, shares in bookmaker Ladbrokes jumped 6.5%.
The Competition and Markets Authority said Ladbrokes and Gala Coral might have to sell about 350 to 400 shops for their planned merger to be "conditionally cleared", but the figure was lower than expected.
On the currency markets, the pound fell 0.64% against the dollar to $1.4518, and dropped 0.68% against the euro to â‚¬1.2952.
(Close): The London market rose more than 1%, recovering most of the ground lost on Thursday.