Updated 5.45pm with new video

Former Nationalist MP and current Law Commissioner Franco Debono unleashed a scathing attack against Prime Minister Joseph Muscat on Saturday, describing him as the "most corrupt politician" in Malta's history.

In a cryptic blog post on Saturday, the criminal lawyer said "the time had come" for him to speak out and warned the Prime Minister that: "tomorrow I would be able to speak better".

"You swallowed it hook line and sinker, because you were always a fool," said his undiplomatic post.

Also on Saturday, the lawyer uploaded a video on Facebook decrying the government's decision to select Marie-Louise Coleiro Preca to head the constitutional convention after she steps down as President. 

The attack comes just a day after he uploaded another contentious post, saying that from all the facts in the public domain one can argue that given the circumstantial evidence, the secret company Egrant belongs to Joseph Muscat or someone close to him.

“Muscat should stop playing hide and seek. I’ve known him since Form 2C and I’ve never known him to be particularly brilliant... The Egrant inquiry didn’t find who Egrant belongs to nor did it find who it doesn’t belong to, because it seems as though it excluded no one,” he wrote. 

Read: PM will drop proceedings against Caruana Galizia if family accepts Egrant inquiry conclusions

The statement came just hours after the Prime Minister said in court he was wiling to drop libel proceedings against slain journalist Daphne Caruana Galizia if her family accepted the conclusions of the Egrant inquiry. 

In another post, Dr Debono thanked those who were encouraging him to stand as a candidate in the European elections. 

Dr Debono served as an MP for the Nationalist Party between 2008 and 2013 but his term will be remembered for his incessant attacks against his own party's Cabinet led by Lawrence Gonzi. After the 2013 election, he was elected Law Commissioner by the Labour government. 

Read: Gonzi and Debono head for showdown