Spark Energy collapse leaves 290,000 without supplier

Fears other challengers will fold amid tough competition and rising wholesale costsAn energy firm with nearly 300,0000 customers has become the biggest electricity and gas supplier to go bust in the UK, fuelling concerns that more challenger firms could fold.Spark Energy is the seventh supplier to fold this year amid pressure from rising wholesale costs and tough competition. The closure will mean the loss of more than 400 jobs at the firm’s headquarters in Selkirk in the Scottish Borders.