SSE and M&S Energy have announced their partnership will end in September after nine years.
That means M&S Energy will no longer provide gas and electricity under the Big Six supplier’s licence.
SSE said there will be no interruption to customers’ supply as M&S Energy customers are supplied under a so-called ‘white label’ agreement, i.e. when the gas and electricity is provided by the Big Six company but sold under the M&S Energy brand.
The companies added: “We will be writing to customers shortly to let them know about all the options available to them when the contract comes to an end in September 2018. SSE and M&S will work to ensure all communications are clear and transparent for customers.”