Speaking to the Daily Telegraph, UK Foreign Secretary Boris Johnson accused London Mayor Sadiq Khan, who holds his former position, for not taking any blame for the poor response to the tragedy, which took lives of 71 people and displaced many others who now live in temporary accommodations.
"The most extraordinary lacuna in the whole conversation about Grenfell is the Mayor of London, a Macavity-like performance by anybody I have ever seen."
"Why did he not take charge? Why did he not find accommodation for the victims? Why was he so spineless and invertebrate? Unbelievable," Johnson exclaimed.
Their Labor colleagues, however, will attend the multi-faith service at London's Saint Paul's Cathedral.
Johnson blasted the "outrageous" move that targets "dedicated public servants," while the sitting Mayor of London escaped any blame for failing to provide any meaningful redress to the victims and their families.
Responding to the Foreign Secretary's criticism, a spokesman for Khan said that Johnson demonstrated "his breathtaking ignorance of the facts and a lack of sensitivity, no doubt motivated by a wish to protect his friends in the council and in the government."
"On the day the Mayor joins the families of those who lost loved ones in the devastating Grenfell fire, who come together to remember those who died; it beggars belief that Boris Johnson has chosen to launch such a bitter attack," the spokesman stated.
The service will be attended by some 1,500 people, including the bereaved, survivors and rescue workers.
British Prime Minister Theresa May and Leader of the Opposition Jeremy Corbyn will also make an appearance, joined by the members of the Royal Family, including Prince Charles, Prince William and Princess Kate.