The legislation, which overhauls existing laws dating back to 1889, is aimed at making it easier to prosecute companies who make corrupt payments abroad.
The Act makes it illegal to offer or receive bribes and to fail to prevent bribery.
Both British and foreign companies are covered, provided they have some operations in the UK. The act also applies to individuals.
The legislation was due to come into force in April 2011, but it was delayed over business concerns about whether corporate hospitality could be seen as a bribe.
In March Justice Secretary Ken Clarke assured companies the act would be implemented in a "workable, common sense" way.
He has since assured companies that they can take clients to events such as Wimbledon and the Grand Prix, so long as the hospitality is reasonable and proportionate.
The government said it did not expect "genuine hospitality" or similar expenditure to fall under the act.
Companies prosecuted under the act must show they have "adequate procedures" in place to stop bribes.
"Adequate procedures" may include providing anti-bribery training to staff, carrying out risk assessments for the markets being operated in, or carrying out due diligence on the people being dealt with.
The Act creates four distinct criminal offences of bribing another; being bribed; bribing a foreign official and (for commercial organisations) failing to prevent bribery.
Earlier this year the DPP, Keir Starmer QC, head of the Crown Prosecution Service said: "While the Act takes a robust approach to commercial bribery, it also applies to individuals who attempt to influence the application of rules, regulations and normal procedures.
"The issues prosecutors must consider before deciding whether to seek my consent to prosecute an individual or an organisation for bribery are clearly outlined, and by making this guidance publicly available, our approach is made open and transparent."
