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 says about 1,700 customers were affected by possible contract breaches. It investigated complaints that suppliers cancelled existing orders and offered new deliveries at much higher prices as the Middle East conflict drove up costs. Customers received refunds for their original orders, but many faced paying more or going without fuel.

Some suppliers have agreed to cover the extra cost paid by affected customers. Those who did not buy replacement oil will instead have their original orders honoured at the agreed price. The CMA is still seeking compensation from other firms and says it is prepared to pursue court-based enforcement action.

The regulator says the price rises largely reflected higher wholesale costs, but heating oil customers have fewer protections than households connected to the gas and electricity grids. It has recommended a new regulatory regime for suppliers to the UK and devolved governments.