Hi Gail
From the information you have supplied we cannot tell you as there are two types of legacy ESA
One is called Income Related (IR) ESA and the other is called Contribution Based (CB) ESA.
If you are on IR ESA then you would be asked to apply for UC, if you are in receipt of CB ESA then you would stay as you are.
You may want to contact your local Welfare Rights Organisation for help; you can find your local Welfare Rights Organisation to help you with advice by clicking on the link below and putting in your post code, it will then come up with a MAP with a list of agencies.
advicelocal.uk Gary