London's stock market rose on Wednesday as the heavyweight energy sector received a lift from news that Royal Dutch Shell has agreed to a huge takeover of BG Group.
Eurozone indices were steady as traders awaited an update on the outlook for US interest rates and looked ahead to the latest action by Greece over its massive debt pile.
London's benchmark FTSE 100 index gained 0.52 percent to 6,997.90 points in late morning deals.
The CAC 40 in Paris rose 0.19 percent to 5,160.80 points and Frankfurt's DAX 30 index fell 0.18 percent to 12,101 points compared with Tuesday's close.
In foreign exchange, the European single currency climbed to $1.0864 from $1.0811 late in New York on Tuesday.
"The Shell and BG mega merger adds 50 points to the FTSE, pulling it into positive territory regardless of the negative sentiment surrounding the European equity markets," said Alastair McCaig, market analyst at IG trading group.
"Today’s proposed acquisition would create the largest company in the FTSE and the second largest oil and gas company in the world behind Exxon."
Shares in BG Group soared 37 percent to 1,246 pence, while Royal Dutch Shell 'B' shares were down 4.89 percent to 2,100.50 pence, with some analysts saying the offer price may turn out to be too large.
Within the sector, Tullow Oil jumped almost 11 percent, BP gained 3.22 percent, while French energy giant Total won 0.99 percent to 48.07 euros in Paris.
"The deal between Royal Dutch Shell and BG Group will prompt sector consolidation," noted Marc Kimsey, senior trader at Accendo Markets.
"The decline in oil prices over the past year has battered some stocks which are clearly now looking attractive. In the last year BG shares fell 30 percent... By comparison sector behemoths BP and Royal Dutch Shell have only shed 10 percent over the same period leaving them in the position of predator rather than prey."
Later Wednesday, the Federal Reserve publishes minutes from its last interest rate meeting, with dealers set to pore over them for clues about when the US central bank plans to announce a hike in borrowing costs.
Markets were cautious meanwhile as Greece faces a Thursday deadline for its next bailout repayment to the International Monetary Fund.
Eurozone deputy finance ministers were meeting on Wednesday and Thursday to seek agreement on Athens's reforms needed to unlock the last tranche of its multibillion-dollar bailout and avert a default.