The Personal Independence Payment (PIP) is a benefit that replaces Disability Living Allowance (DLA) for people aged 16 to 64.
The charity Contact have produced an excellent guide to PIP for parents (and other benefits at 16). Download it here (PDF 1.09MB).
You can claim PIP by calling the PIP New Claims number - 0800 917 2222. You will need to complete a Personal Independence Payment (PIP1) claim form, which is usually done over the phone.
You will then be sent a questionnaire called How Your Disability Affects You (PIP2), which must be completed and returned within a month.
Most people will then be asked to attend a face-to-face assessment (known as a ‘consultation’). This will be performed by a professional from either Atos or Capita.
A case manager at the DWP will then decide whether you're entitled to PIP (and at what rate), and will send you a decision letter.
If you disagree with the decision you can ask the DWP to look at it again. This is known as a Mandatory Reconsideration. AdviceNow have a Mandatory Reconsideration Request Letter Tool that will help.
If you are unhappy with the new decision, you can appeal directly to Her Majesty’s Courts and Tribunals Service. AdviceNow have produced a booklet called How to Win a PIP Appeal, which might help.