LONDON — All 75 high-rises in Britain that have been tested for fire safety since the Grenfell Tower tragedy have failed, a leading government official said on Monday, raising concerns that even more buildings may have to be evacuated while emergency repairs are undertaken.

Addressing the House of Commons, Sajid Javid, the minister for communities and local government, said all 75 towers in Britain whose cladding had so far been tested for combustibility had failed. He said hospitals and schools would also be tested to ensure they had not been built with cladding that could easily catch fire.

Hundreds of families were ordered to evacuate apartments in the five high-rise buildings of the Chalcots Estate in northwest London on Friday night in an urgent scramble after it emerged that, among other safety risks, the buildings had exterior cladding similar to that used on Grenfell Tower. At least 79 people died in Grenfell Tower on June 14, in London’s deadliest fire in more than a century.

An estimated 4,000 residents of the more than 800 apartments in the Chalcots Estate were advised to leave their homes, many of them resorting to sleeping on air mattresses in a nearby hospitality center. But at least 100 residents refused to budge, even as local officials were knocking on their doors and urging them to get out.