In the UK there is a police presence at the security points rather than 'agents'. They didnt seem to be singling out any specific people for searches. They probably searched/questioned 50% of people checking in on July 24.

By contrast, there was a complete absence of security at McCarran on August 7. I didnt see anyone searched, and the whole process of checking in (including paying for excess luggage and checking in golf clubs at the oversize), through security and into the departure lounge took 20 minutes. No need for me to get there 3 hours early after all. I was told there was more security and delays in the domestic terminal than for international.