The country's biggest gas storage site, Rough, returned from maintenance as planned on Wednesday, a spokesman for site owner Centrica said.
Rough, a key source of winter gas, is able to inject gas on Wednesday.
Injection operations are commencing in line with the plan to return Rough back to operations, the spokesman said.
Centrica hopes to have the store ready to withdraw gas at full flow from October 1.
Withdrawals have not been possible since the facility was shut on February 16, 2006 after a fire.
The storage site was 96 percent full when it was closed for maintenance on Sept 7. It will play a pivotal role in keeping up gas supplies on cold winter days when North Sea gas production is insufficient to meet high demand.