Profits at energy giant Shell have remained buoyant despite a recent weakening in crude oil prices.

Shell posted underlying profits of £2.08 billion in the three months to June 30, up 51 per cent on a year earlier.

That contributed to a 73 per cent rise in the year so far to £4.51 billion although the quarterly performance was weaker than the record £2.43 billion seen in the first three months of the year.

Crude oil prices have fallen sharply since the end of the Iraq war, although the Brent average of 26.05 US dollars a barrel is still higher than the second quarter average of 25.05 US dollars a year earlier.

Shell was further helped by the North American natural gas market continuing to see high prices in the period between April and June.

The company said the outcome for the rest of the year remained uncertain.

It added: "Crude prices for the second half of this year will depend on Opec supply in response to the return of Iraqi exports to the oil markets and on the state of the global economy."

Yesterday's figures were ahead of market expectations, although shares remained close to their opening mark after Shell told shareholders that it did not plan to buy back any more shares this year.

Chairman Sir Philip Watts said the interim results were evidence that the company's strategy was working well.

He added: "We are doing what we said we would do and I am confident we will continue to be highly competitive."

The company's core division covering exploration and production saw second quarter earnings rise to £1.26 billion from the £1.13 billion reported a year earlier.