Police Check

Hie everyone

I am planning on applying for a police check for my immigration processing. But what I am wondering is how long is a police check valid for? Coz I don't want to do it too soon and by the time I go for an interview maybe it will be expired.
Any input much appreciated.

Thanks LT

As far as I am aware 12 months and when applying in the UK average is 40 days from applying to receiving. Also don't forget you will need one for every country lived in longer than 6 months

By the countries lived in does it give time frame for instance if you left your country 20 years ago.