Judge has ruled I pay back my ex the money i owe her,I want to make sure she doesn't get a penny?

How easy is it to apply to go bankruptcy in the UK, how long doest it take? Judge has ruled i pay her back �100 per month, also CSA are taking �200 out of my wages. I have other debts too so i want to declare myself bankruptcy so she wont get a penny. I have bad credit anyway