If you are suffering from bad credit, then SIM only contracts are the perfect alternative.  SIM only contracts are much easier to be accepted for than a standard contract that comes with a handset:

• Easier Credit Checks – Since no phone is supplied with SIM only tariffs, networks do not have to worry about recouping the cost of the handset and are more likely to approve people with bad credit history.
  
• More Minutes & Texts – Networks operators can offer more inclusive monthly minutes and texts since no handset is supplied; passing on the savings to customers.
  
• 30 Day Rolling Contract - Getting a pay monthly contract no longer means being tied down to 12 or 18 month contracts. SIM only contracts are for 30 days and you can cancel at anytime with no charges or commitment, otherwise your contract will roll onto the next month.

Networks Offering a Sim Only Contract:

3 Mobile SIM Only Contracts

Vodafone Sim Only Contracts

With SIM only contracts, you are certainly more likely to be approved if you have a poor credit rating. If you already have a handset you like, then why bother getting a new one?