LONDON'S top flight index stayed in positive territory as investors cheered better-than-expected results from blue-chip giants BP and Standard Chartered.

The FTSE 100 Index was up 23.6 points to 6284.5, with the oil major climbing more than 4% as it improved its performance despite booking hefty losses caused by the stubbornly low oil price.

But Standard Chartered was the biggest riser, surging close to 10%, as it swung back into profit in the first quarter and drove down its bad debts.

The Asia-focused bank said statutory pre-tax profits hit 589 million US dollars (£404 million) in the three months to March 31, up from a 4.1 billion US dollar loss (£2.8 billion) in the fourth quarter last year.

The London market was also given a helping hand from the rising oil price, which stepped up 2.5% to 45.61 US dollars a barrel on the back of the weakening dollar.

Across Europe, Germany's Dax and the Cac 40 in France were both down 0.3%.

Sterling was up 0.9% against the dollar at 1.461, as US consumer confidence dropped to 94.2 this month after rising to 96.1 in March.

The pound was also up 0.5% against the euro at 1.291.

In stocks, BP rose 15.6p to 375.9p as it posted replacement cost losses of 485 million US dollars (£335 million) for the first three months of the year, down from losses of 2.2 billion US dollars (£1.5 billion) in the previous three months.

But, on an underlying basis, the blue chip group defied expectations for a loss, posting adjusted profits of 532 million US dollars (£367 million), although this was down sharply on the 2.58 billion US dollars (£1.8 billion) profits a year earlier.

Standard Chartered raced ahead, up 50.8p to 571.4p, after loan impairment losses reached 471 million US dollars (£323 million) in the first quarter of this year, down from 1.13 billion US dollars (£756 million) in the three months to the end of December 2015.

Group chief executive Bill Winters said: "Although trading conditions in the first quarter remained challenging, we continue to make good progress on our strategic objectives."

He said the bank would hit its restructuring cost target of three billion US dollars (£2 billion) by the end of the year while it was also on track to deliver one billion dollars (£686 million) of gross cost savings in 2016.

Drugs giant AstraZeneca was the biggest faller after it entered into a licensing agreement with Ironwood Pharmaceuticals Inc for the US rights for Zurampic, a drug used for the treatment of gout.

Shares were down 2% or 85p to 3999p.

Meanwhile, Costa Coffee owner Whitbread stepped up more than 2% as strong growth from the coffee chain and its Premier Inn hotels business bolstered profits.

The firm saw shares rise 102p to 3969p as annual pre-tax profits climbed 11.9% to £546.3 million as sales across Whitbread grew 12% to £2.9 billion.

The biggest risers in the FTSE 100 Index were Standard Chartered up 50.8p to 571.4p, Paddy Power Betfair up 390p to 8765p, BP up 15.6p to 375.9p, and Lloyds Banking Group up 2.4p to 70p.

The biggest fallers were AstraZeneca down 85p to 3999p, Burberry Group down 24p to 1210p, Glencore down 3p to 152p, Inmarsat down 17p to 929.5p.