BP plc delivered the worst of a poor set of quarterly results among top oil companies on Tuesday, slashing $5 billion off the value of US assets and undershooting expectations with its operating result.

Investors are hoping for a deal with the authorities before the US elections

The British oil company is struggling under the weight of litigation over the 2010 US Gulf oil spill and a row with its Russian partners. Analyst Richard Griffiths of Oriel Securities said the figures were “testing the faith” of investors and on a divisional basis “missed at every level”.

The $5 billion charge included $2.7 billion for the declining value of US refineries and $2.1 billion for US shale gas assets which are suffering a slump in prices, and for the suspension of its Liberty project in Alaska.

The shale gas and refinery writedowns do not come as much of a surprise. Other companies have being doing the same.

But BP also took an extra $847 million provision for the 2010 US Gulf oil spill - bringing the total set aside for the disaster to $38 billion or well over two years worth of profits at current prices.

Investors are hoping for a deal with US authorities before the US elections but BP warned there was still “significant uncertainty” with regard to its potential obligations there.

BP had nothing new to say about its dispute with the co-owners of TNK-BP, who on Monday blocked the payment of dividends from the business. The charge tipped BP into a loss for the quarter of $1.4 billion.

Adjusted for the charge and other one-offs, profits on a replacement cost basis were $3.7 billion, down from $5.7 billion a year ago and below expectations of around $4.4 billion.

Analysts said an unexpectedly large loss of output as a result of maintenance in the US Gulf – a problem which also hit rival Royal Dutch/Shell in the quarter – was partly to blame for the miss.