Renting a car without a credit card is indeed possible, especially if you have a debit card. However, even then you may be subjected to a credit check. The car rental company may scan your credit for signs of recent financial problems, and if red flags appear you may be declined. Not all agencies make such checks, however, making a debit card your best bet for renting a car if you don't have a credit card.
Contact rental car agencies well in advance of your rental, if possible. Avoid problems at the rental car counter by making a reservation and stating that you will be renting without a credit card and would like to pay by debit card. Speaking with the rental car company by telephone is important because the various rental car companies have a dizzying array of policies for renting to customers without credit cards. For example, some major rental car companies will allow you to rent a car with a debit card--and no credit check--if you are picking up the car during a trip and can show proof of a return ticket home aboard a plane or train. Other companies won't accept a debit card at all from someone renting a car in their home market. Even more confusing are requirements that differ by the city. According to the CreditCards web site, one major car rental company will accept debit cards in Atlanta, but not in Chicago. Quirky rules like those make it important to call ahead before renting.
Check the balance on your debit card account. Make sure you have enough available cash on your debit card to pay for the cost of the rental--and an additional deposit that could be up to £325. The extra money is held to cover incidentals, such as bringing the car back without a full tank of gas or keeping it an extra day or two.
Pick up your car at the rental car counter, with or without a reservation. Present your debit card and agree to any credit check, if asked. Go on to the next option if you'd rather rent a car without a debit card.
Rent your car and pay cash at some locations. You should definitely call ahead if you plan to rent using cash. According to the CreditCards web site, one major rental car company requires cash customers to make reservations up to six weeks in advance and pay a £9 processing fee to qualify for the rental. The qualification includes sending in proof of address, such as utility statements or copies of your lease, along with paycheck stubs.