The banking giant moved to block unapproved messaging services from work devices earlier this month. "Like many organisations, we only permit the use of approved channels for communicating about business matters, whether internally or externally," says a NatWest statement. The decision comes amid regulatory scrutiny of communications channels that make it more difficult to retrieve messages. Last year, energy regulator Ofgem has fined Morgan Stanley £5.41 million over the use by traders of WhatsApp messages on private phones to discuss market transactions. In the US, regulators have hit a host of financial services firms with fines totalling nearly $3 billion in total over the use of unofficial communication tools like WhatsApp and iMessage.