Krook, the landlord in Charles Dickens’ Bleak House, is probably literature’s most famous victim of spontaneous combustion. Critics have long denounced his demise as outlandish. But there are many buy-to-let landlords around the country – especially after the Bank of England’s shock-and-awe half-point increase in interest rates to 5 per cent last month – who right now feel themselves in danger of succumbing to the same fate.