AST's have been around since 1988, BTL mortgages since 1996, that is a bit more than overnight.
Banks would not take the rental income received into consideration on a mortgage for a home prior to 1996, that is when BTL mortgages arrived, after the Association of Residential Letting Agents...
BTL mortgages were introduced to create more rental properties, this should have had the effect of reducing rents as supply increased, unfortunately net migration of 250,000 people a year has somewhat filled the gap.
BTL landlords have had a good run, but when interest rates rise, many will be...