As a student, it's likely that landlords will insist that you have a guarantor. A guarantor is someone who agrees to pay your rent if you don't pay it, and is usually a parent or close relative.
If you have a joint tenancy the guarantor needs to understand that they will generally have the same liabilities as you do. This will mean that even if you pay your rent your guarantor could be responsible for paying any rent that you owe and potentially the cost of any repairs for damage to the property. The liability of the guarantor will depend on what has been agreed in the guarantor form; the guarantor needs to check the tenancy and the guarantor form and possibly negotiate to limit their liability.
This model guarantor agreement is provided by Unipol Student Homes and is an example of an agreement that can limit guarantor liability to one person’s share of the rent. You could show this to landlords if you're trying to negotiate a more limited guarantor liability.
Need more information on guarantors? Check out this information from Citizens Advice or Shelter.
Don't have a guarantor?
There are services that can act as guarantor for a fee. Some guarantor services are: