Because private medical insurance is designed to cover the unforeseen, you cannot take out a policy to get treatment for a medical condition that has already developed recently.

Exclusions to cover
Health Insurance will almost certainly not cover all your health and medical needs.
The following are more than likely to be excluded under the policy terms and conditions:

• Emergency treatment – you will almost certainly be treated by the NHS
• Existing or previous health problems
• Incurable or chronic conditions (including the terminal stages of cancer)
• Long-term illness (e.g. diabetes, asthma, multiple sclerosis) – although initial treatment and relief of acute phases might be covered
• AIDS-related illnesses – although you may be covered for the initial diagnosis and a limited stay in hospital
• Treatment on a kidney machine (renal dialysis)
• Routine check-ups from GPs, dentists or opticians
• Preventative medicine such as vaccination or cancer screening
• ‘Palliative’ treatment designed to relieve rather than cure
• long-term hospital or nursing care
• complementary medicine – although some policies pay for osteopaths and chiropractors if your GP refers you
• normal pregnancy and childbirth
• abortion
• vasectomy and sterilisation
• some out-patient costs (e.g. glasses, hearing aids and prescriptions)
• the services of your GP (e.g. the fee for filling in your claim form)
• self-inflicted injuries or suicide attempts
• treatment related to drug or alcohol abuse
• cosmetic surgery
• psychiatric treatment
• dental problems

Pre-existing conditions
Private medical insurance policies always have some sort of clause covering claims for pre-existing conditions.
Some will pay out for the treatment of existing (or foreseeable) conditions only if the health insurer agrees to cover them when you take out the policy.
In this case the health insurer assesses the risk of paying out on the basis of a medical questionnaire and possible medical examination by an approved doctor.

You may find that cover is adjusted or premiums loaded accordingly and sometimes that you are refused cover altogether.
Some will cover existing conditions on a ‘moratorium basis’, meaning that any illness or condition that has occurred in the five years before taking out the policy will not be covered for a specified period – usually two years – after the policy is taken out.
This may well apply to any medical condition that occurs as a result of a pre-existing condition so you should always read the cover terms properly before purchasing a policy