A Japanese parliamentary panel said the Fukushima nuclear accident was a “man-made disaster”, according to reports.

On the same day nuclear power was pumped into Japan’s grid for the first time since all its plants were closed after the crisis, the panel’s report found the meltdown was “preventable”.

On 11 March 2011, three nuclear cores at the Fukushima Dai-ichi plant went into meltdown after a major earthquake and 15-metre tsunami disabled the power supply and cooling of three reactors, releasing radioactive material.

The Fukushima Nuclear Accident Independent Investigation Commission accuses the Government, Tepco and regulators of collusion.

The group’s chairman Kiyoshi Kurokawa also speculates in the report’s introduction that cultural conventions including “reluctance to question authority”.

The report could bring the plant’s operator, Tokyo Electric Power Co (Tepco) under further intense scrutiny, as it criticises the firm for failing to prepare enough in case of an electricity outage.

The investigation is said to have included 900 hours of hearings and interviews with more than 1,000 people.