The prime minister rejects accusations of a lockdown by stealth, but the hospitality sector says they have already lost 2 billion pounds ($2.7 billion) as people are not going out.
New travel curbs mean isolation and testing for Britons arriving to France.
The polls are open in North Shropshire. An ultra safe-seat for the Conservatives could be under threat, as the area elects a replacement for MP Owen Paterson.