By Lars Mucklejohn Revolut is among three new firms signing up to the banking industry’s answer to 999 after it emerged that it had outstripped all the UK’s major banks in official fraud complaints. The London-based banking app is to join the 159 hotline created by Stop Scams UK, an industry body backed by the Financial Conduct Authority and Ofcom. It will become 159’s 20th member once it has finished onboarding in the coming weeks. Ringing the 159 number puts callers directly through to staff at their banking provider, who can give advice to help work out whether they are being targeted by sc…