The Public Accounts Committee highlighted the way some firms seconded staff to the Treasury to advise on technical issues in the drafting of legislation - only for the individuals concerned to return to advise clients on how to use those laws to avoid tax.
Through their work in advising government on changes to legislation they have a detailed knowledge of UK tax law, and the insight to identify loopholes in new legislation quickly.
We have seen what look like cases of poacher, turned gamekeeper, turned poacher again, whereby individuals who advise government go back to their firms and advise their clients on how they can use those laws to reduce the amount of tax they pay.
More top news
Paul Gascoigne has spoken about his ongoing battle with alcoholism, admitting that "the only person who can save me is me".
A quick text can have serious long-term implications for a mobile phone users' spine, experts have warned.
The terror threat posed by violent extremists has "evolved", one of the UK's most senior counter-terrorism officers has warned.