Long lines have formed at vaccination centres in Britain as people heed the government’s call for all adults to get booster shots to help withstand a coronavirus “tidal wave” driven by the Omicron variant.

In a televised announcement late on Sunday, Prime Minister Boris Johnson said everyone 18 and up would be offered a third vaccine dose by December 31 — less than three weeks away, and a month earlier than the previous target.

“We are now facing an emergency in our battle with the new variant, omicron,” Johnson said. He said boosters would “reinforce our wall of vaccine protection” against an anticipated “tidal wave of omicron.”

While the online appointment booking system will not be open to under-30s until Wednesday, Johnson said any adult could show up at a walk-in centre to get a booster.

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