No electricity firms will be prosecuted for last year's power failures, the government has announced.

It was revealed on Thursday that energy minister Stephen Timms has told electricity firms they must act on recommendations from the Engineering Inspectorate to ensure the problems do not happen again.

The London Underground was brought to a standstill last August by a power failure caused by a fuse failure. Train travel in South London and Kent was also hit.

London mayor Ken Livingstone described the incident as an "absolute outrage".

Just days later, parts of the West Midlands were also hit by a series of power failures.

Energy firms now have a detailed - but confidential - report from the government which calls on them to "enhance the robustness" of their systems.

DTI lawyers have told the firms that if they fail to act on the report they will face legal action.