Former Canadian Prime Minister Jean Chretien, whose government was engulfed in a scandal over misuse of funds, has defended his actions.
Mr Chretien maintains that he acted in good faith
Mr Chretien is accused of mishandling money intended for a sponsorship and advertising programme.
It is alleged that huge sums were given to advertising agencies with ties to his party for little or no work.
Mr Chretien is only the third Canadian prime minister ever to testify before an official inquiry.
Denying the charges on Tuesday, Mr Chretien said the campaign was needed to keep the country together.
Between 1997 and 2001, $188m went to a project designed to promote national unity in the primarily French-speaking province of Quebec.
Neckties and corkscrews
But a report by the country's auditor-general says at least half the money was siphoned off to benefit advertising and communication agencies with ties to the Liberal Party.
Mr Chretien says the programme was intended to boost national unity after a 1995 referendum vote on secession which almost resulted in Quebec breaking away from Canada.
"For the next eight years the unity of Canada was my number one priority as prime minister," he said.
The commission investigating the programme learnt that 480 neckties printed with the Canadian flag were purchased for the sum of $36,600 as part of the programme.
Some $10,000 was also spent on corkscrews embellished with a Canadian logo.
Mr Chretien acknowledges that some mistakes were made and says those who were aware of what was going on should be punished.
But he said he had never knowingly acted illegally.
"Those mistakes that were made in good faith can be excused," he said.
"If some people acted in bad faith or for personal gain, they betrayed the prime minister, they betrayed my government and they betrayed the country."
The scandal has also tainted the leadership of current Prime Minister, Paul Martin, who was the Liberal Party finance minister during the period of the alleged misuse of funds.
Mr Martin is due to testify on Thursday, when he will become the first sitting prime minister to appear before a public inquiry since 1873.