LONDON — Britain’s health secretary has confirmed that batch testing has been completed for the first 800,000 doses of the Pfizer vaccine, which will be ready for use starting early next week.

Matt Hancock told lawmakers on Wednesday that the U.K. has preordered 40 million doses of the shots, enough for 20 million people to get the required two shots each. The doses will be tested in batches for safety.

“This is a monumental step forward. It’s no longer if there’s going to be a vaccine, it’s when,” he said. “This is a day to remember, frankly, in a year to forget.”

Hancock says distribution of the vaccine will be “one of the biggest civilian logistical efforts that we face as a nation.” He says the shots will first be distributed by hospital hubs and 50 of these are “ready to go” next week.

Doctor’s offices, pharmacies, conference centers and sports venues will later play a part in distributing shots.