The FTSE 100 opened higher, up 0.46% or 24.52 points to 5,337.14, on encouraging news from the oil sector.
Investors also responded positively to results of European stress testing which saw all the major banks pass.
BP rose 2.68% to 409.3p on news embattled BP chief executive Tony Hayward is expected to resign tomorrow.
Elsewhere in the resources sector, Tullow Oil says it has found a new oil field, causing its shares to jump 5.43% to £12.43.
However, it was a mixed picture for the UK's banking stocks as Barclays increased 2.68% to 309.5p, while Standard Chartered was down 0.25% to £18.19.
In Europe, banking shares drove the major indices higher. France's CAC 40 rose 0.42% to 3,622.23 led by Societe Generale, BNP Paribas and Credit Agricole, while Germany's Dax was up 0.32% to 6,186.28 topped by Commerzbank.
On Wall Street, US stocks made further advances as investors responded positively to European bank stress test results.
The Dow Jones closed up 0.99% or 102.32 points to 10,424.62.
Despite posting a 12% rise in second quarter profits, McDonald's was the biggest faller, down 2.1% to $69.90.
In contrast, Verizon rose 3.78% to $28.02 as second quarter losses were not as bad as expected.
In Japan, the Nikkei gained 0.77%, or 72.70 points, to 9,503.66 as hopes for robust corporate results from firms including Sony and Toyota buoyed the market.
