This means the East Midlands city will not move forward with the opening of social spaces, due to take place on July 4, and will have some liberties withdrawn.
The health secretary added: “Having taken clinical advice on the actions necessary, and discussed them with the local team in Leicester and Leicestershire, we have made some difficult but important decisions.
“We have decided that from tomorrow non-essential retail will have to close.
“And, as children have been particularly impacted by this outbreak, schools will also need to close from Thursday, staying open for vulnerable children and children of critical workers as they did throughout
“Unfortunately, the clinical advice is that the relaxation of shielding measures due on the 6 July cannot now take place in Leicester.
“We recommend to people in Leicester, stay at home as much as you can and we recommend against all but essential travel to, from and within Leicester.
“We will monitor closely adherence to social distancing rules and will take further steps if that is what’s necessary.”
Cases are rising week-on-week in the city – from 39 cases in the week to June 19 to 41 cases in the week to June 26.
Soldiers from the Royal Logistics Corps have been pictured at a new mobile coronavirus testing site at Evington Leisure Centre in Leicester this morning.