The trial has opened of two former Ogilvy & Mather ad agency executives accused of defrauding the US government in 1999 while working on an antidrugs campaign.

The court in Manhattan heard allegations that Shona Seifert, former O&M senior partner and executive group director, and Thomas Early, ex-senior partner and director of finance, deliberately over-billed the Office of National Drug Control Policy by hundreds of thousands of dollars.

The pair's defence, however, claims they were naïve players at an agency out of its depth in dealing with a complicated federal account. Both pleaded not guilty to the charges of defrauding the government and making false statements. If convicted they could face five years in jail.

On the first full day of evidence the court heard from prosecution witness, former O&M account executive Melissa Cunningham. She says she was asked by Siefert to change her time sheets and bill more hours to the ONDCP account than she had in fact worked.

Siefert's defence lawyer accused Cunningham of changing her story several times in return for immunity from prosecution. He also pointed to her alleged uncertainty as to who had issued the order to inflate the time.

Prosecutors say the conspiracy to defraud was set in motion when Ogilvy staff discovered an anticipated revenue shortfall on the ONDCP account.

The agency agreed in 2002 to pay $1.8 million (€1.3m, £956k) to settle civil accusations by the government.

Data sourced from AdAge (USA); additional content by WARC staff