Prime Minister Joseph Muscat has challenged Opposition leader Adrian Delia to table a vote of confidence when asked if he was willing to shoulder political responsibility for the political ramifications of the Daphne Caruana Galizia murder investigations.

This prompted a mass walkout of the Nationalist MPs who left the chamber in protest amid strong words from both sides.

It happened during a highly-charged sitting characterised by constant warnings from the chair that the sitting could be adjourned, unless MPs would restrain themselves.

Addressing the House immediately after question time, Opposition leader Adrian Delia asked the Prime Minister if he was willing to shoulder political responsibility over the alleged involvement of his outgoing chief of staff Keith Schembri whom he said was “accused” with Ms Caruana Galizia’s murder.

In his reply, the Prime Minister refuted Dr Delia’s claims that the country’s institutions had been eroded, saying the very fact that the police had made progress on this case disproved the Opposition’s claims.

“Institutions are working and we are defending them,” the Prime Minister said.

“My job is to ensure that such a big case is solved under my watch,” he said prompting a show of support by government MPs.

“If the Opposition leader thinks I must resign, he has the ways and means to table a vote of confidence,” he added. Moreover, the Prime Minister pointed out that Mr Schembri had not been charged with murder.

Dr Delia reacted, saying the Prime Minister was adopting double standards as in the last legislature members of Cabinet had been sacked for much less serious reasons.

“Given that the Prime Minister has not shouldered political responsibility, the Opposition will no longer engage with the government,” Dr Delia said as he led all PN MPs out of the chamber, leaving the two independent MPs Godfrey and Marlene Farrugia as the only Opposition representatives present.

Though the sitting proceeded with a debate on amendments to the Eco-Contribution Act, Justice Minister Owen Bonnici focused exclusively on the ongoing controversy regarding Ms Caruana Galizia’s murder.

He said the Opposition was intent of eroding public trust in the country’s institutions, including the set procedure of giving a Presidential Pardon which had been in place for decades.

Dr Bonnici said the Prime Minister was doing his utmost to solve this heinous murder. He added that the Prime Minister’s comments were only meant to keep the public abreast of developments in the investigation.