All retailers need shop insurance. There is no legal requirement to have an insurance policy in force (except for employers liability) but it is less than sensible to trade without it.
A standard policy will include cover for different sections, one of these is for money. Shopkeepers do still accept significant amounts of cash, especially the smaller retailers.
If you have a policy in force it will cover cash on the premises, in transit to and from the bank and also overnight. With cash being so theft attractive, commercial insurance companies are not too keen to insure high amounts.
Usually, a policy will give cover for between £3 and £5,000 on the business premises during the day. Overnight, you will be lucky to get over £500 unless it is in a safe.
For this £500 cash overnight, that is not in a safe, you need to read the terms and conditions of your policy wording. It may well be that you have fairly onerous terms. Some of the main insurers will only provide cover if the cash is removed from the till and stored elsewhere on the premises (not necessarily in a safe). Where it is stored elsewhere, the policy will state that the till drawers need to be left open.
The reason for leaving the till drawers “out” is that any prospective thief may look through the shop window and, when seeing the empty till drawer, decide that there are better pickings elsehwere.
It is only a small point but if an insurer investigates (after a claim) and the cash was forcibly stolen from a till, you will not be covered.
If you are in any doubt as to the terms and conditions, give your broker a call, this will be easier than you having to read the documents yourself.