Heating oil customers whose orders were cancelled during a price surge are set to receive compensation of up to £350 each after an investigation by the Competition and Markets Authority (CMA).

The watchdog said about 1,700 customers were affected by possible contract breaches. Customers had been refunded for cancelled orders, but many faced paying substantially more for a replacement delivery or going without fuel. The price surge followed the war in the Middle East; heating oil reached 123p a litre at its April peak, up 92%.

Several suppliers have agreed to compensate affected customers after the CMA contacted them. Those who bought more expensive replacement oil will be paid the difference, while customers who did not replace their oil will have their original orders fulfilled at the agreed price. The CMA remains in talks with other suppliers and says it is prepared to seek court-based enforcement if they do not compensate customers voluntarily.

The watchdog found that higher prices largely reflected rising wholesale costs. It has recommended a new regulatory system for heating oil suppliers, including a supplier register and minimum standards for handling cancellations.