HMRC issues warning letters over missed MTD deadline The taxman has issued over 100,000 TV licence-style warnings to self-employed people who failed to submit their tax returns online using specialist software. In total, 1.2m businesses will be forced to comply with the new Making Tax Digital (MTD) regime. About 490,000 should have completed their first return by August but 120,000 have yet to register. An HMRC spokesperson said: “We want businesses to join MTD without fear of getting it wrong – HMRC are not penalising those transitioning. Our letters are the latest in a series of communications to encourage those remaining businesses to join the 1.1m who already have signed up and ensure they know how to access support to do so if they need it.”