BP upped its provision for litigation and claims costs stemming from the 2010 Gulf of Mexico oil spill by $1.1bn (£724m) last year, bringing its estimate of total litigation and claims costs relating to the incident to $26.8bn (£17.7bn).

In an earnings update issued yesterday (3 February), the oil giant said it had upped its estimate of litigation and claims costs by $435m (£287.5m) in the fourth quarter of last year.

The company also warned there was potential for costs to rise further before the various legal cases it is embroiled in conclude.

It said: "The magnitude and timing of all possible obligations in relation to the Gulf of Mexico oil spill continue to be subject to a very high degree of uncertainty."

The spill at the site of the Deepwater Horizon oil rig in the Gulf of Mexico in 2010 killed 11 oil rig workers and resulted in the release of over three million barrels of oil into the ocean, devastating wildlife.

Five years on, there are still multiple legal proceedings relating to the spill. The law firms handling these include Kirkland & Ellis, Gibson Dunn & Crutcher, Dentons and Arnold & Porter.

In December, those four firms appealed the terms of the Economic and Property Damages Settlement Agreement, drawn up in 2012 for those affected by the spill, at the instruction of the oil giant, but their submission was rejected by the US Supreme Court.

Yesterday's statement also revealed that in another case related to the spill BP Exploration and Production (BPXP) has until 9 April to seek a review by the US Supreme Court of a Court of Appeals decision last month that, along with petroleum giant Anadarko, BPXP is liable for civil penalties under the Clean Water Act.