On Wednesday last week, a horrific fire ripped through a 24-storey residential tower in west London.
Opposition politicians also say the government ignored recommendations from a 2013 review after another London fire killed six people.
The British government Sunday scrambled to contain political fallout from the London high-rise inferno that has claimed at least 58 lives as officials focused on building materials that may have spread the fire quickly.
Grief and disbelief at seeing a tower that had been home to up to 600 people reduced to a burned-out shell turned to outrage and anger.
"I have always said I will be accurate about what I know, so the next figure of those presumed dead and missing will be released tomorrow, Monday 19 June".
Did cheap cladding panels fuel the fire?
He promised an "exhaustive" criminal investigation that would also look at a major refurbishment of the tower completed previous year.
Mr Cundy said: "Sadly, as of this morning, I am afraid to say there are now 79 people who we believe are now dead or missing and we have to presume they are dead".
"The residents of Grenfell Tower, families who have lost loved ones, and the emergency services who have been working so hard to help them have been through some of the most harrowing and traumatic experiences imaginable", Theresa May said.
"During recent visits in Manchester and London, I have been profoundly struck by the immediate inclination of people throughout the country to offer comfort and support to those in desperate need", the queen said in a statement.
Cundy says the new number may change as investigation continues.
Thousands observed a minute's silence in tribute to the victims of the Grenfell Tower Fire. He asked anyone who was in the tower and survived to contact police immediately. The job's contractor has said the work met all fire standards.
May, criticised for keeping her distance from angry residents during her visit to the charred remains of the apartment building, said on Saturday that the response to the disaster had been "not good enough".
Last week, the government had announced that people rendered homeless because of the blaze will be given at least £5,500 from an emergency fund.
May said after the meeting Saturday that there have been "huge frustrations" in the community as people tried to get information. British health authorities say that 19 fire survivors are still being treated at London hospitals, and 10 of them remain in critical condition.
He told reporters the "awful reality" was that it might not be possible to identify all the victims. She also said she will receive daily reports from the stricken neighborhood.
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