Britain's tough new anti-bribery legislation finally took effect today, and was greeted with a warning from the head of the Serious Fraud Office that foreign companies would be in his firing line.

Recent government guidance said foreign companies would not be subject to the Bribery Act's tough new penalties simply because they had a share listing in London. But SFO chief Richard Alderman used newspaper interviews to warn that shouldn't be read as letting overseas businesses off the hook.

“You bet we will go after foreign companies. This has been misunderstood. If there is an economic engagement with the UK then in my view they are carrying on business in the UK,” he told one newspaper.

The Act gives the UK authorities powers to prosecute companies that pay bribes or fail to prevent the payment of bribes anywhere in the world, if they have a meaningful business connection with the Britain.