Sparks are set to fly as the taxman targets electricians as part of a crackdown on unpaid tax.
Leeds accountancy firm Mazars warned electricians they should appoint a tax adviser.
“HMRC is well aware that the black economy continues to thrive... but not for much longer if it has its way,” said Mazars partner Tony Maleham.
HMRC has also issued notices to colleges and other distance learning companies requiring details of gross payments made for teaching, examining and invigilating from which no PAYE has been deducted for the years ended April 5, 2009 to 2011.
HMRC is looking to collect an extra £4bn before next April, says the firm, and has issued notices to 17 organisations to identify potential targets for inquiry including electrical associations for member lists.