A pair of front-runners in London's mayoral election may soon have their campaign finances scrutinized.

A compliance audit has been requested to determine if mayoral hopefuls Paul Paolatto and Paul Cheng campaigned before the official start of last year’s election.

Londoner Lincoln McCardle has requested a compliance audit at city hall.

McCardle asks if actions taken by Paolatto and Cheng before the campaign period violated election rules.

Specifically, Paolatto advertising his blog and the content of Cheng’s website.

Rules forbid candidates from raising or spending money until they registered at city hall May 1.

The complaint also asks if Cheng exceeded the $25,000 limit on candidate contributions.

If an audit is launched a three-member committee will investigate.

Neither Paolatto nor Cheng would comment Wednesday on their pre-campaign activities.