Nothing stops an investor from buying a house with a mortgage and having the renter pay a mortgage with their rent, but apart from that, banks will only lend on the number of homes; and managing 50 or more houses may be a nightmare, even if you hire a mortgage broker in London for property management business.
To begin, look for houses with potential growth when purchasing homes to rent.
Purchase distressed properties that require some work and will return a profit once the work is completed. You look for properties with a minimum of a 100% capital gain return (effectively doubling my money on the purchase). As they are becoming increasingly scarce, many people opt for properties with such a 50% capital gain. Even yet, the money you put in the property is now worth 1.5 times what you invested.
Buy the property with the help of hard money loans. Sometimes, you may find a loan or mortgage that would lend up to 75% of the property's AFTER-REPAIR value, reducing the amount of money you need to put into it.