Ms. Smith said too many mistakes had been made, and that she had felt let down by the National Health Service, whose workers have often been lauded by many in the public and the media as heroes. “No one was a hero to my dad,” she said.

Britain is slowly emerging from a monthslong lockdown and Mr. Johnson has promised a “great summer” ahead. Outdoor sports resumed this week, and as groups of six are now allowed to gather outside, crowds have flocked to parks in London to bask in the sun.

Numbers of new infections and deaths have plummeted in recent weeks, raising hopes that some return to normalcy would come soon. With more than 30.5 million people having received a first dose of the vaccine — 45 percent of the country’s population — Britain has rolled out one of the fastest vaccination campaigns in the world.

Yet health authorities have warned that the third wave of coronavirus infections that has swept through continental Europe may also reach Britain.

And bereaved families said returning to normal would be impossible.

“For those of us who lost someone during the first wave, last spring, we’re reliving everything now,” said Ms. Goodman. “Last night I couldn’t sleep because exactly a year ago I learned that my father had Covid, and he died days later, so looking forward to going back to normal is so difficult for us.”

With the pandemic still raging, the hand-painted hearts opposite Parliament may continue spreading for weeks, even if at a slower pace. Still, Mr. Fowler said he hoped this would stop soon.

“When this is done, please, no more hearts,” he said.