Barclays Bank and retrospective legislation on tax
28 February 2012 Last updated at 14:02 GMT
Allister Heath said UK tax rules are "much too complex and riddled with loopholes" and they need to be changed.
The City AM editor said the government was right to shut down tax schemes like the ones as used by Barclays Bank - but there were problems with retrospective changes as it gave too much power to the tax authorities.
He spoke as Barclays was accused by HM Revenue and Customs of using two schemes to avoid substantial amounts of tax and it has been ordered it to pay £500m.