There are no rules which state how much cash you can have within your property, however there are some very good reasons why holding large amounts of cash at home is not a good idea.
The first reason is security. If you are burgled and you leave cash sums in the property unprotected in a drawer or cupboard it may be difficult to claim for this on your insurance. Providing evidence that you hold large amounts of cash at home is not easy and proving to your insurer that it has been stolen may be difficult. If you are keeping large sums in a safe, then ensure that the safe insurance rating covers the amount you hold. I.e., if you have £2,000 in a safe be certain that the safe is at least £2,000 cash rated AND that your insurance company have approved the use of your particular safe. It is advisable to use an AiS Approved safe, if you are storing cash.
Certainly, from an insurance point of view, it is not a good idea to hold large sums of cash at home, particularly if this cash is takings from a business. In the event of theft, your insurance company would not cover you for the loss of business takings kept at home. If safe storage on your business premises is not possible, always aim to bank your daily takings rather than taking it home.
Other things worth bearing in mind would be the purpose of holding cash at home. If you are ‘saving up’ for something, it is probably better to have a bank savings account rather than a jar in a cupboard. A bank will also give you some form of interest on your savings although it is currently very little! But at least your money is secure from theft in a safe.
Bank mistrust is a common factor when people keep large sums of money at home. This has probably been driven by high profile bank collapses in recent years. Legislation is in place to protect the investor from loss of savings due to bank collapse, meaning this is no longer a reason for holding large cash sums at home. Certainly, even the most basic level of bank security is going to be better than keeping it in your sock drawer at home.
Lastly, keeping large amounts of cash at home can be viewed with suspicion by certain authorities such as HMRC and the Police. If you are under suspicion and your home is raided, you would need to prove that the cash has been obtained by legal means and not by non-declaration of earnings or even criminal dealings. Failure to do this will result in the money being seized as part of an investigation.