Not guilty pleas as trial starts for aides to Ontario ex-premier McGuinty

David Livingston and Laura Miller have pleaded not guilty to charges over Ontario's gas plant scandal. The former top aides to ex-premier Dalton McGuinty are alleged to have deleted emails about the cancellation of two proposed gas plants, costing tax payers around $1.1 billion.

The cancellation of the proposed gas plants cost taxpayers an estimated $1.1B

David Livingston and Laura Miller, top aides to former Ontario Liberal premier Dalton McGuity, have pleaded not guilty. (Handout/Queen's Park)

A trial of two former top political aides in the Ontario premier's office finally began today in Toronto with the accused pleading not guilty.

David Livingston and Laura Miller are charged over allegations they illegally destroyed emails in the office of former Liberal premier Dalton McGuinty.

The defence hammered the prosecution for providing "sketchy" information they say warranted an adjournment.

The lawyers also said the prosecution has dropped witnesses without saying why, and notes of interviews police and Crown had with witnesses were completely deficient in detail.

The lawyers want the judge to review prosecution notes and order the Crown to say why witnesses were dropped.

The emails at issue were about the Liberals' decision to cancel two gas plants just before the 2011 election, which ended up costing taxpayers about $1.1 billion.