BP said it expects to write down between $4bn and $5bn from its gas and low-carbon energy divisions in its transition businesses as it refocuses on fossil fuels under chair Albert Manifold. BP said the writedown would not affect underlying profits when it reports full-year results in February, and it has been trying to sell a stake in its solar business Lightsource while cancelling hydrogen projects in the UK, Oman and Australia. BP said oil trading was weaker in its final quarter and that Brent crude averaged $63.73 a barrel in the fourth quarter versus $69.13 in the prior quarter. BP said net debt fell to between $22bn and $23bn at quarter end from $26bn at the end of the previous three months.