Giovanni Kessler, the head of Olaf, the EU's anti-fraud office remains hopeful that his immunity will be reinstated despite a recent court decision.

The European Commission lifted his protection in March on allegations that he authorised illegal wiretaps in a tobacco lobbying scandal some four years ago.

Student or retired? Then this plan is for you.

The affair saw John Dalli, a Maltese EU commissioner for health, booted out of office.

But if Belgian prosecutors convict Kessler, the head of the Brussels-based anti-fraud bureau, he could be jailed for two years and fined, in a major embarrassment for the EU.

Kessler has taken the EU commission to the Luxembourg-based European Court of Justice (ECJ) to get back his protection.

He says that if he goes on trial, it would imperil Olaf's independence and investigations.

He also says that he should stay immune, pending the final ECJ judgment, which could take months or up to a year, for the same reasons.

On 20 July, the ECJ president threw out the latter appeal, allowing the Belgian case to move ahead.

But Kessler's press office is playing down the verdict “interim measures" as having no bearing on the “substance”of the matter at hand.

"It did not rule on the validity of the arguments in law put forward by the Director-General [Kessler]. The case on substance is therefore ongoing and will proceed as per the Court's usual rules and timelines," Olaf told EUobserver by email on Tuesday (2 August).

The alleged wiretap incident concerns a phone call in 2012 between a tobacco lobbyist, Inge Delfosse, and a Maltese restaurant owner, Silvio Zammit.

Zammit claimed to represent Dalli and that, together, they could change EU laws in return for millions of euros.

Delfosse, as part of Olaf’s probe, had called Zammit from Olaf’s office in Brussels, while Zammit was unaware that he was being recorded.

That is illegal in Belgium.

It is also said to violate article 7 of the EU's charter of fundamental rights.

Olaf’s office says it does not "carry out any telephone tapping”, however.

It told EUobserver in 2014 that “wire-tapping” is when you put a bug in a suspect’s phone, not when you record a call without the suspect’s knowledge.

The Delfosse-Zammit conversation produced nothing useful for the investigation.

The EU commission has declined to comment on any aspect of the Kessler case.