does it matter if anyone finds out your national insurance number?

[Dean]

I went to police station and someone handed it in woohoo Was not expecting that! There are some honest people in my town afterall

NI can be used for fraud yes but unlikely. You're lucky though!

[-Danube-]

Glad to see you got the stick back.

But yes an NI number can be used and i feel it's quite valuable to a fraudster.

Passports and other official documents are relatively easy to make fake copies of under another name but your NI number is unique to yourself and is hard to fake.

An NI number is often needed when opening a bank account (like and ISA) or credit card. A bank will often ask for your NI number, a passport and some kind of utility bill or letter with your name and address at the top. The latter are both normal things which fraudsters easily fake, but with your NI number they can do a little more. For example they could open an ISA account in your name using your NI number and then they would be able to use your tax free savings allowance for that year without you knowing. Doesn't sound like a very profitable scam but if a person was to open many ISA accounts at different banks they could easily end up being able to store money being used for crime in Tax-free accounts, leading to more money being used for crime.