Terrorism & extreme political activity

Questions:

• A man down the street works in a research facility and there is a person that is hanging around his house looking suspicious, what do I do?
• I am due to fly, what are the restrictions regarding hand luggage / baggage presently in force?
• I have received a letter and there appears to be white powder in it, what should I do?
• I have seen a website condoning/encouraging violence against certain groups of people, what should I do?
• I have seen someone that I think is acting suspiciously, filming the outside of a police station/ mosque/ chemical factory/ research facility/ military base etc, should I report it to the police?
• I think that a local organisation collects for a charity but I think the money is going to extreme political activists, what can I do?
• I want to take some photos / video footage in public, is it now illegal?
• Please can you tell me what the definitions of terrorism and terrorist are?
• The man next door to me has a St George's flag on his window and holds meetings every week and has Nazi memorabilia in his house
• There is a man who rents a garage next to mine and I think he has some explosives in there, who do I tell?
• What do I do if I see a suspicious package on the train/ at the airport /in a shopping centre?
• What is radicalisation and what are the warning signs to look out for?
• What is the PREVENT programme?
• What should I do in the event of a terrorist attack?