Media playback is unsupported on your device Media caption BP's chief executive Bob Dudley: ''This is a historic moment for BP''

BP has signed a joint venture with Russian energy firm Rosneft to exploit potentially huge deposits of oil and gas in Russia's Arctic shelf.

The "strategic global alliance" will see the firms exchange expertise in exploring the region.

As part of the deal Rosneft will take 5% of BP's shares in exchange for approximately 9.5% of Rosneft's shares.

It is BP's first deal since the Deepwater Horizon spill last year, which cost it billions.

The BP shares stake is worth just under $8bn (£5bn).

"BP executives see this as the first piece of good news since that disastrous oil spill in the Gulf of Mexico last April," said the BBC's business editor Robert Peston.

But he said the deal was a controversial one, with Russia not seen as an entirely transparent society nor as a stable place to do business.

'Historic'

"This unique agreement underlines our long-term, strategic and deepening links with the world's largest hydrocarbon-producing nation," said BP's chief executive Bob Dudley.

Analysis For BP executives it's a hugely exciting moment - the first bit of what they see as seriously good news since that devastating oil spill in the Gulf of Mexico last April. For BP what matters is that the area of the Russian Arctic to be explored has the potential to produce as much oil as the North Sea in its heyday. But the deal will be hugely contentious. First Russia is widely viewed as not a desperately stable environment for Western businesses. Second it involves Rosneft, Russia's biggest oil company, taking a 5% stake in BP worth just under £5bn. Rosneft is 75% owned by the Russian government. So it will look to many as though the Russian government is taking a 5% stake in a company with strategically important oil reserves all over the world, including - of course - the US.

He said the "historic" deal would "create value, deliver growth, and meet the world's demand for energy".

Mr Dudley said the agreement would meet the needs of consumers, shareholders and governments.

The firms will explore in three areas - known as EPNZ 1,2,3 - on the Russian Arctic continental shelf.

The areas covers 125,000 square kilometres in an area of the South Kara Sea.

"Our future joint venture will utilize the experience and expertise of BP, one of the leaders in the global oil and gas industry," said Rosneft's President, Eduard Khudainatov.

"This project is unique in its complexity and scale both for Russia and the global oil and gas industry. We see it as the next step in developing our relations with BP."

'Unexplored'

Referring to the Deepwater Horizon blast Mr Dudley said that the firm had "learned many lessons over the past year".

He also said the Russian deal had not been precipitated by the backlash it had experienced in the US because of the Gulf of Mexico spill.

We are creating an entirely new strategic alliance between what I know are two great companies Bob Dudley, BP chief executive

Since the rig disaster in the US Gulf of Mexico BP has been disposing of assets.

Mr Dudley is the former chief executive of Russian joint venture TNK-BP, and was forced out of the country in 2008 after falling out with other shareholders.

But he said he was pleased to now be working with Rosneft in "one of the world's last remaining unexplored basins".

"We are today building a relationship between BP and Rosneft that has been forged over 12 years but going far beyond anything that has gone before," he said.

"We are creating an entirely new strategic alliance between what I know are two great companies."

Joint research

Media playback is unsupported on your device Media caption UK Energy Secretary Chris Huhne: ''It's a ground-breaking deal''

BP and Rosneft have also agreed to set-up an Arctic technology centre in Russia which will work with Russian and international research institutes to develop technologies for the extraction of hydrocarbon resources from the Arctic shelf.

UK Energy Secretary Chris Huhne hailed the agreement as a groundbreaking development.

"From what we know, it sounds like it's potentially good for BP," said Phil Weiss, analyst at New York equities firm Argus Research.

"BP gets access to resources, Rosneft gets access to expertise and knowledge."

However in the US Congressman Edward Markey, who is leading Democrat on the House Natural Resources Committee, called for a review of the deal by US regulators.

Return to profit

BP had a terrible 2010 with the Gulf of Mexico spill, which is going to cost them at least $40bn.

But in November BP announced it was back in profit in the three months to September after last quarter' s record loss.

The firm said its replacement cost profit for the period was $1.85bn (£1.15bn), as against the $17bn loss recorded from April to June.

The previous loss reflected the massive costs of the Gulf of Mexico oil spill crisis.