Biofuel company Firefly said it would develop a plant in Harwich, Essex, to convert sewage into sustainable aviation fuel (SAF).

It said it expects to begin supplying the lower carbon fuel from around 2028 and has reached an agreement with Wizz Air to provide up to 525,000 tonnes of SAF over 15 years.

Utility company Anglian Water has committed to providing biosolids, a product of its wastewater treatment process, to Firefly for an initial pilot SAF facility.

SAF is made from sustainable sources, meaning its production involves using around 70% less carbon than conventional jet fuel.

It can be used in a maximum blend of 50% with kerosene without the need for any modifications to jet engines.

However, SAF is currently several times more expensive to produce than conventional jet fuel.

Firefly chief executive James Hygate said biosolids are "kind of disgusting stuff" but "an amazing resource".

"We're turning sewage into jet fuel. I can't really think of many things that are cooler than that," he said.

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Paul Hilditch, the company's chief operating officer, said: "There's enough biosolids in the UK for more than 200,000 tonnes of SAF.

"That's enough to satisfy about half of the mandated SAF demand in 2030.

"We're not the only answer - we need the other routes to SAF - but this new route to SAF has the potential to move the needle, it has the potential to be a significant contribution to UK Saf supply.

"And not just the UK of course. Anywhere in the world where there are people, there's poo."

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Firefly said it is in the process of obtaining regulatory approval for its system to be used to fuel aircraft.

Wizz Air announced a new aspiration to power 10% of its flights with SAF by 2030.

Under the government's SAF mandate, at least 10% of the fuel used by airlines in the UK must be made from sustainable feedstocks by 2030.