I reckon we, in in western nations, keep doing what we do, and modify our methods a bit. This applies to all radicals, and crime really.
When I think about any issue of violence, my thought goes to what we, as a society, would look like if the authorities and experts were doing nothing. We know what failed states look like, Somalia, Haiti etc, and our nation does not look like them.
We don't look like Afghanistan, that has a radical Government, or Pakistan where religious and tribal attacks result in hundreds of dead.
We have strict gun laws, so we don't have school shootings. The US has slack gun laws and lots of mass shootings, so we know our gun laws work.
Yes, we have horrific terror attacks in the Uk, but how do we know if we would have more or less if Government, of any brand, were not doing what they do. Same as with gun laws, how do we know what we do is not working ?
So I think we do what we already do, most definitely with more resources and cash of course, and our Parliament should listen and debate any new laws the experts think would help reduce the risk.
If the experts say enhanced checks, travel bans etc, then put it to Parliament and debate it.
Totally yes, we should do all we can to prevent any attacks at all. But are we ready to deal with the loss of freedoms that entails.