The top share index powered higher on Tuesday morning, propelled by a string of strong corporate results and a rally in the oil price.

London's benchmark FTSE 100 index <.FTSE> was up 53.77 points, or 1 percent, to 5,724.89 by 1145 GMT.

Despite falling in the past two sessions, the FTSE is up 2.8 percent since the start of the month -- on track for its best showing since a strong rally in October and, potentially, the second best monthly performance in the past year.

The balance of the newsflow has been a small net positive in terms of expectations ... The forecast risk for 2012 numbers isn't as great as it was, said Ian Williams, a strategist at Peel Hunt.

The income you are getting on equities versus other asset classes -- with gilts yielding 2 percent and cash yielding nothing -- is one of the reasons we are seeing this buy on dips mentality.

ARM Holdings led the gainers with a 4.4 percent rise in the share price after the British chip designer, whose technology powers Apple's iPad and iPhone, reported a 45 percent rise in quarterly profit and said its growth would continue to outstrip the industry.

Solid results also helped boost BSkyB , with shares in Britain's dominant pay-TV group adding 3 percent.

National Grid gained 2.2 percent as Britain's biggest energy distributor said the outlook for the year remained positive and announced plans to increase its dividend -- a key factor for investors looking for a steady return at times of ultra-low bond yields.

In a reverse of Monday's trading, miners <.FTNMX1770> and energy companies <.FTNMX0530> led the advance among the sectors.

North Sea Brent crude jumped $3 per barrel, pushing shares in FTSE heavyweight oil major BP nearly 3 percent higher.

Sentiment also brightened in Europe, after the European Union agreed to a German-inspired pact for stricter budget discipline, which supporters hope will tackle the underlying causes of the region's debt crisis, and Greece reported significant progress in its debt restructuring talks.

The FTSE volatility index -- a gauge of investor risk aversion -- eased to 19.6, after hitting its highest in nearly two weeks on Monday <.VFTSE>. But analysts remained cautious.

While risk has rebounded, we remain cautious: repeated promises of imminent agreement over the past two weeks have delivered nothing as yet, BNP Paribas' analysts said.

On the loser board, grocers Tesco and Morrisons eased after data pointed to Britons cutting back on the number of items they buy and switching to cheaper goods as their free cash is squeezed by rising prices, muted wages growth and austerity measures.

(Additional Reporting By David Brett; Editing by Jon Loades-Carter)