How do you redouble your efforts to defeat terrorism, how do you stop a person driving a truck into any group of people?
Theresa May says the UK must redouble its efforts to defeat terrorism, as she condemned the "brutal murderers" behind "horrifying" attacks like that in Nice.
The prime minister said Britain stood "shoulder to shoulder" with France after a lorry drove into a crowd killing 84 and injuring 202.
Downing Street says a "small number" of Britons were injured in Nice.
Meanwhile, UK police are asking for any Britons in France with footage of the incident to come forward.
And police forces across the UK have been asked to review security arrangements at major events over the next week.