The British company is a 13.6pc partner in the Angola LNG development, which will export gas that would otherwise be burned off as waste from oil fields.

BP plans to invest $15bn in Angola over the next decade and the LNG plant is one of its biggest start-ups worldwide this year.

The project, led by US giant Chevron, was originally supposed to start shipping cargoes early last year but has repeatedly been delayed, with Angolan national oil company officials blaming ‘technical problems’.

The plant would be the only new LNG facility in the world to start shipping this year and could eventually see cargoes sold to Britain if gas prices are high.

Martyn Morris, regional President of BP in Angola, said: “We were hoping [first cargoes] the middle of May but I think it’s more likely to be the end of May or early June.

“This is a huge piece of business for Angola, getting into the LNG market for the first time.”

Oil analysts at Nomura last week highlighted Angola LNG as one of four key developments in the sector about which investors were seeking “reassurance” in the upcoming first-quarter results reporting season.

Angola is Africa’s second-biggest oil producer but most of the so-called “associated gas” that is also produced during oil drilling deep in the Atlantic Ocean is burned off into the environment by “flaring”.

The Angolan government has pushed the industry to cooperate on creating more than 500km of pipeline infrastructure to take the gas to the new LNG plant where it will be cooled to minus 160 degrees C, allowing it to be transported for sale on giant tankers.

Angola LNG was originally intended to export to Mississippi, but the shale gas revolution in the US has left the country with surplus gas.

Mr Morris said: “We are now targeting selling it to Europe and the far east. I wouldn’t be at all surprised whether some if it comes in to the UK at some point. Clearly [in] the gas market in far east prices are much higher than in Europe, but Europe is much higher than the US.

“It takes longer to get things to far east then Europe. It was going to be very easy just tootling across the Atlantic, but things have changed.”

Flaring is restricted because it is environmentally damaging, so finding an alternative use for the gas will enable oil companies such as BP to maintain higher oil production.

New projects such as BP’s giant PSVM floating production, storage and offloading vessel, which began oil production in December, will also be hooked up to the LNG plant.

At peak annual production capacity of 5.2m tonnes of LNG and natural gas liquids, Angola LNG should ship more than 70 cargoes a year.

Britain relied on LNG for 47pc of its gas imports in 2011, falling to 28pc last year amid lower UK demand and as cargoes went to meet strong demand and higher prices in Japan.