Mental capacity means being able to make your own decisions at a time when that decision is needed.
Some people can make everyday decisions like what to eat for lunch, but they may not be able to make other more complicated decisions such as whether they need a serious operation.
Being unable to make decisions when it is needed is called ‘lacking capacity’
There is a law called the ‘Mental Capacity Act’ and it protects people who can not make decisions about certain things for themselves.
The Act means you can have an advocate to help you make complicated decisions if you have no one else.