Letting out your home without Consent to Let either from your mortgage company (if you have a mortgage) or your insurers if you have normal household insurance or if your property is leasehold anyway e.g. a flat, is very dangerous.
To do so you are committing mortgage fraud.
Your insurance may be invalidated.
What if tenant dies or gets injured? If you get sued you may have no protection and lose everything.
What is your tenant damages or destroys the property? If you claim, you may get nothing.
You must discuss any potential holiday let e.g. AirBnB or other holiday let service or longer shorthold assured tenancy with your lender/insurers.
If leasehold, you must check the terms of the lease as well as the conditions for subletting.