In an exclusive article featured in today’s Accountancy Age, Dave Hartnett said these ‘spivvy’ firms specialised ‘in promoting the kind of tax avoidance schemes others would not touch’, and would blatantly skirt disclosures by filing shoddy paperwork or refusing to notify authorities of new schemes altogether.

‘We have come across…instances of inadequate or late disclosures, disclosures made on the wrong forms or to the wrong office, or even failures to disclose what appear to be notifiable schemes,’ Hartnett said.

‘Such failures are not always innocent error, with the evidence pointing to a conscious attempt to delay disclosure purely in order to prolong the life of the scheme.’

Hartnett’s comments follow a period of relentless pressure on firms defying the disclosure rules.