LONDON (Reuters) - Britain’s top share index powered ahead on Monday, helped by gains among commodity-related firms though shares in Paddy Power Betfair slumped after its CEO announced plans to step down.

People walk through the lobby of the London Stock Exchange in London, Britain August 25, 2015. REUTERS/Suzanne Plunkett/File photo

Britain's blue chip FTSE 100 .FTSE index ended the session with a gain of 0.3 percent at 7,531.94 points, outperforming a broader decline in the pan-European STOXX 600 .STOXX index.

Miners and energy stocks gave the biggest boost to gains, with the two sectors contributing more than 20 points to the index and lifting it to a 7-week high.

The FTSE ended last Friday with its best week so far in 2017, and has so far gained around 5.5 percent year to date.

Shares in Glencore GLEN.L, Rio Tinto RIO.L, BHP Billiton BLT.L and Anglo American AAL.L all rose between 2.3 percent to 3.1 percent, helped by firmer iron ore prices. [MET/L]

“It’s the second Monday on the trot that we’ve had a strong open for iron ore prices, and also copper is still knocking up against those recent multi-year highs, the dollar’s pulled back a bit from Friday’s spike, so all of that is playing in favour even if oil prices are lower on a bit of uncertainty going into the OPEC meeting,” Mike van Dulken, head of research at Accendo Markets, said.

“The overall environment for metals prices and their miners is still pretty positive.”

Oil & gas heavyweights BP BP.L and Royal Dutch Shell RDSa.L gained 1.1 percent and 0.7 percent respectively.

Elsewhere shares in Paddy Power Betfair PPB.L tumbled 4.7 percent and posted their worst day in five months after its CEO Breon Corcoran announced plans to step down.

“The decision by Breon Corcoran to step down as Paddy Power Betfair CEO has come earlier than most would have expected,” analysts at Davy Research said in a note.

“The timing is certainly less than ideal given the particularly noisy regulatory backdrop at present and the fact that the group is yet to complete its major platform migration project,” Davy Research analysts added.

Outside of the blue chips, British mid caps .FTMC also rose 0.1 percent, helped by gains in the materials sector and financials.