Give 1 to 2 months warning to give people time to make preparations then apply a national extreme 3 week lockdown where no one leaves the house with exception of emergency services, NHS staff, those in life threatening condition, carers of those cant survive alone and vital maintenance staff
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With the virus contained in each household and not having chance to spread it could starve and eliminate it from the UK. Then we deny entry to the country to anyone with a positive test to prevent it re-entering the UK after which the vaccine the masks and the social distancing would no longer be necessary.