Retrospection

There's something particularly nasty about retrospective legislation, after all prosecuting someone for something that wasn't a crime or was legal before the legislation was voted upon is neither fair nor just. That's one of the reasons for all I did not particularly care for the defendants in the Lawrence case, they were tried only because the government rescinded the law on double jeopardy after the first prosecution failed. It's also why I disagree with this...
BBC.

Barclays Bank has been ordered by the Treasury to pay half-a-billion pounds in tax which it had tried to avoid.
Barclays was accused by HM Revenue and Customs of designing and using two schemes that were intended to avoid substantial amounts of tax.
The government has taken the unusual step of introducing retrospective legislation to end such "aggressive tax avoidance" by financial institutions.
Tax rules forced the bank to tell the authorities about its plans.
The government has closed the schemes to retrieve £500m of lost tax and safeguard payments of billions of more tax in the future.
BBC business editor Robert Peston has been told by Barclays that it is surprised by HMRC's reaction to the two schemes, which it believed to be in line with those used by other banks.
Our business editor says it is highly embarrassing for Barclays, because Britain's big banks have all signed a code committing them not to engage in tax avoidance.
However, he adds that Barclays may end up paying no more than £150m of additional tax.

Unlike the government, or indeed the BBC it seems, for all I'd like Barclays to pay all they are due to pay in taxation, I don't blame them one bit for trying to avoid paying unnecessary taxation, so all of a sudden Barclays are liable to pay extra money that last month they didn't have to pay at all and this is just wrong, I don't mind so much the governments attempts to close loopholes I do mind when they close a loophole and then demand money from before the loophole has been closed.
Sure, there are some who will say that because Barclays had promised not to engage in tax avoidance, though it does appear that what Barclays did is similar to what other banks did. However the banks duty is too its shareholders, not the taxpayer and certainly not the government.
You have to wonder what will be retrospectively applied next, seems UK governments have a penchant for introducing it...