This type of cover is also known as 'Mortgage Payment Protection Insurance' (MPPI) because the cover is generally designed to cover the cost of your mortgage in the event that you can’t work due to accident, sickness or unemployment.
Most policies only pay out for a maximum of 12 months and monthly payments are commonly capped at £1,500 or £2,000 or based on a percentage of your income. Therefore, if you have a mortgage above this level you will need to make provision to cover the surplus. Consideration should therefore be given to savings and/or payment from your employer in the event of sickness/unemployment to determine whether cover is required.