It's a big change.

Under the existing law, companies can only be held liable for facilitating evasion if the directors were involved.

The new rules will make a company liable even if a director had no idea about what was going on, unless it can show it had reasonable procedures in place to prevent it.

The goal is a change in culture and better controls.

The announcement has been seen as an attempt by David Cameron to regain the initiative after a week of intense scrutiny of his financial affairs.

It also comes ahead of a summit he is holding next month, which is aimed at tackling corruption in all its forms.

But the move was already in the pipeline.

It was originally announced just over a year ago as ministers sought to crack down on practices exposed by a Swiss tax evasion scandal.

The new law will affect a wide range of companies, particularly those in the financial sector.

Many will have to overhaul their procedures as they did with similar anti-bribery legislation in 2010.

Some argue that British firms will be put at a disadvantage.

They say the aggressive approach taken by the U.S., for example, has put off some financial services firms from operating there.

The government has already made some changes to its original proposals that were welcomed by businesses.