If your course is shorter than a year, you must show immigration officials that you have enough money in your bank account to pay for the entire course as well as your living expenses for the first nine months of your stay in the UK, which are calculated at £1265 per month for London and £1015 per month for the rest of the UK.
A statement of bank accounts a passbook of the building society/savings account variety a dated and signed letter from a financial institution confirming your ownership of the account, its account number, and the existence of funds in the account for at least 28 days.
You are permitted to use your parents' bank account, but you must submit a birth certificate and an accompanying letter from your parents stating that they have granted you permission to do so.