Former QFL president Michel Arsenault made it clear was finding it difficult to cooperate during his first day of testimony at the Charbonneau Commission.

Throughout the day, the exchanges were testy between Arsenault, the focus of many wiretaps heard so far at the commission, and prosecutor Sonia Lebel.

Arsenault’s perceived attempts to change the subject instead of provide direct answers added to the tension, even prompting some finger-snapping from Lebel to get his attention.

The inquiry wants to know his precise relationship with Tony Accurso, an entrepreneur facing hundreds of fraud charges, and the first question from Lebel was to ask him to define his relationship.

Caught off guard, Arsenault said he still has lunch with Accurso on occasion, but doesn't consider him a friend.

Later, he told Lebel he was available until Friday, because after that he had “a trip scheduled.”

As the leader of the QFL (known in French as the FTQ) from 2007 until 2013, Arsenault's name has been repeatedly mentioned at the inquiry into corruption in the construction industry.

On the stand on Monday Arsenault opted to defend the 'success' of the QFL and its investment fund, saying it had excelled in creating employment for Quebecers.

Arsenault denied allegations that he knew of a fast-track system to help friends of the QFL-construction obtain financing from the QFL solidarity fund.

Lebel then asked Arsenault if this success, and the 600,000-strong QFL membership, had been used to manipulate political events in Quebec.

"Well, it's an advantage," said Arsenault, explaining that as QFL leader it was very easy to be in contact with politicians.

However he did point out it could not be abused.

"Of course, if you start calling the ministers all the time then after a few weeks they'll get together and they will no longer speak to you."

In recent weeks it's been alleged that in 2009 Arsenault planned to pressure Parti Quebecois leader Pauline Marois to stop demanding an inquiry into corruption.

Marois and other PQ ministers have said that the QFL was unable to stop the PQ from joining the CAQ in demanding a corruption inquiry.

Other witnesses have also said that Arsenault was very well aware of mafia ties to the union, and that the union's investment arm favoured projects presented by Tony Accurso to the point of refusing to fund Accurso's competitors

Wiretaps that have already been presented at the inquiry confirm that Arsenault was well aware of mafia infiltration in the union.

Arsenault tried very hard to prevent those wiretaps from being heard at the Inquiry, pushing the matter to the Court of Appeal, but lost.

On several occasions, wiretaps revealed that Arsenault did not intervene when the ex-boss of the QFL’s construction union Jean Lavallée was collecting bribes, or when director general Jocelyn Dupuis was defrauding his union with inflated expense-account claims.

In November 2013 an investigation showed that the QFL Solidarity Fund invested $3 million in a company part-owned by Marois's husband Claude Blanchet, despite investors worried that the investment made no sense.

Arsenault resigned soon after the report, and was then grilled by MNAs at a special hearing to discuss the allegations of trying to curry favour with the leader of the opposition.