With Let to buy you can make two mortgages at the same time, it involves you leaving your home before you sell and renting it, hiring a loan to compare the new property.
Usually people use this strategy because they have not yet been able to find a potential buyer and do not want to lose money on the sale of the old property, so they rent their house until a potential buyer appears.
What is the difference between let to buy and buy to let?
A let to buy mortgage is intended for people who live on a property and want to keep it to compare a new one, they can choose to sell the house and settle the new home loan a little later or let them rented.
A buy to let mortgage is discouraged for people who want to compare a home for investment.