Britain's grid operator has been accused of covering up operational failures that allegedly increased the risk of blackouts.
Shadow Energy Secretary Claire Coutinho has written to the Information Commissioner's Office calling for an investigation after alleging senior figures at the National Energy System Operator instructed control room staff not to keep permanent records during periods of system stress, in order to avoid creating an audit trail.
Speaking in the House of Commons, she said: "If true, this is nothing short of a scandal."
In her letter to the Information Commissioner, Ms Coutinho said: "I have been contacted by whistleblowers who allege that, during periods of system stress, senior Neso managers have instructed operators in the control room to keep 'live documents' with no version history."
She added: "This is allegedly in order to ensure that there is no audit trail or records of how key operational decisions are made and ensure that full records are not preserved for the purposes of Freedom of Information."
Energy minister Michael Shanks accused Ms Coutinho of "scaremongering", but said the allegations were serious and should be shared with the department if supported by evidence.
A Neso spokesman denied the claims, saying: "Despite unprecedented weather conditions across Great Britain and Europe in June, the GB electricity system remained secure and no customers were disconnected."
He added: "All operational decisions are taken by authorised personnel within established procedures, and it would be false to say otherwise. Neso does not instruct its employees to avoid retaining records. Our priority is the secure operation of the GB electricity system."