A customer who has a contract for interruptible service which enables the supplier to interrupt supply of gas at short notice and the buyer to pay a lower tariff for the gas. Low-priority service offered to customers under schedules or contracts which anticipate and permit interruption on short notice. Often in a gas transportation contract, it is possible that under certain circumstances that additional capacity (in excess of ‘firm capacity’) be made available. Whilst for instance the UK Interconnector is obliged, subject to physical and operational conditions, to make such additional capacity available whenever possible, availability may be interrupted at times and this capacity is therefore described as ‘interruptible capacity’.