But he said the government had sent conflicting signals.
Sir Keir told TimesRadio: “The messages have been broadcast everywhere.
“You have received messages from the government saying go out for a drink, others saying you are responsible, careful – I think the message has been very poor in the past few weeks.
“Today is a huge day, and it’s a real test.
“We supported the relaxation of the restrictions and we supported the government in this regard.
“But, we have been very aware of the risks, so we say to be very careful, the virus has not disappeared.
“My message to the government is that this is a big test for you.
“We are helping you to ease the restrictions, but you must be above the risk.
“And that means things like testing, tracking and tracing really have to work. And there must be a much better way to deal with local epidemics. “