If you see someone with a gun in a public place, call 999 but do so without drawing attention to yourself.
If you have any information about gun crime or believe someone has a gun without a licence, even if they are looking after it for someone else you can call 101, report anonymously online or email.
If you want to stay anonymous call Crimestoppers on 0800 555 111, a national charity who will pass on your information without taking any of your personal details.