Tony Hayward, BP's chief executive, was last night touring the Middle East to reassure the oil giant's partners, as sources said the company is still trying to drum up interest in its shares among Gulf investors.

BP confirmed that Abu Dhabi, rumoured to be interested in taking a stake, was "on Mr Hayward's itinerary" following a stop at the company's operations in Azerbaijan. A spokesman insisted that Mr Haywood was there to offer assurances about the company's stability but would talk about investments "should there be any interest".

BP has ruled out any new shares - either as a placing or a rights issues - but could encourage a new white knight investor to provide a backstop on the declining share price.

The tour comes as BP's management remains under intense pressure to deal with its financial situation in the aftermath of the Gulf of Mexico oil spill. BP's market value has dropped by 50pc since the accident on April 20 killed 11 men and triggered the catastrophic leak.

It is understood that Sir Bill Castell, BP's senior independent director, has been leading a round of talks with shareholders. Sources suggest that BP's leadership team will stand down as soon as the leaking well is plugged. As the senior non-executive director, Sir Bill's role is to liaise between shareholders and management - and smooth over any change over at the top.

The Daily Telegraph has also learned that BP bosses are seeking to calm the concerns of top institutional investors by claiming they are ready to roll out a "robust defence" as soon as the oil leak is capped.

Investors have been told about a "Plan B" which is being secretly worked on by teams of lawyers in answer to criticism that they are failing to defend the company from public attacks. One top ten shareholder said: "We've only heard one side of the story so far. BP has to get the problem solved first but after that we expect the company to come out fighting."

The investors have also voiced their concerns about suggestions that BP could issue shares to bolster its finances. One investor said: "There will be a stink about issuing shares, the company doesn't need either the capital or a row over pre-emption rights. We've made it clear that any new investor must buy shares in the market and support the price."

Instead the company could do a multi-billion pound bond issue for more support which would also underline confidence in its financial position. Experts said the market would support an issue of as much as 10bn.

The developments came as:

BP's oil slick spread deeper into Louisiana's delicate inland wetland areas and tar balls from the spill were confirmed on beaches in Texas.

High waves delayed BP's efforts to catch more oil from the leaking well. It is currently picking up 25,000 barrels per day and hoped to increase this by 10,000 barrels yesterday.

BP's share price rose 3.7pc in London to 345p as drilling for its relief well advanced ahead of schedule.