This from the Financial Times:

The UK’s financial regulator is probing the use of private accounts by foreign exchange traders amid allegations they traded their own money ahead of clients orders

  • So far there is no evidence this happened, its still at the early stage: “The Financial Conduct Authority has asked several banks to investigate whether traders used undeclared personal accounts, two people close to the situation said”
  • At least a dozen traders across six large banks have been suspended, none of whom has so far been formally accused of any wrongdoing
  • There has been speculation for a while that some might have used private accounts (PAs) at spread betting firms to gain advantages from their inside knowledge

UK probes private accounts of foreign exchange traders (gated, but can be read with a free registration)