Doubts over the Serious Fraud Office's (SFO) future and cuts to its budget are casting a cloud over the Bribery Act coming into force today.
Campaigners and politicians have fought for legislation bringing Britain into line with global anti-corruption norms for at least the last decade.
But, on the day the Bribery Act finally comes into force, real concerns remain about the extent to which the legislation will be enforced.
The SFO faces budget cuts of 25% from 2010/11 to 2014/15. Unlike many other government agencies, which saw increases in the previous years, its budget had already shrunk by 26% since 2008/09.
"Now the Bribery Act is in force it's essential for the government to give the Serious Fraud Office the political and financial backing it needs to investigate and prosecute," Labour MP Hugh Bayley told politics.co.uk.
"I've put down a question to find out how much money will be made available. For every million pound bribe, somebody is losing a million pounds and it's a very serious crime which is why parliament changed the law to stop it happening."
Under the Bribery Act, companies which have a presence in the UK - whether they are based here or not - could face prosecution if employees give or receive a bribe.
A corporate offence of failing to prevent bribery also comes into force today, making senior executives liable if the bribe took place on their behalf and they failed to prevent it.
Other offences include being bribed and, for a commercial organisation, failing to prevent bribery.
Writing for politics.co.uk, Transparency International's Robert Barrington and Tearfund's Melissa Lawson said they had "significant concerns" about the "current political will to resource its effective enforcement".
"The government guidance undermines key features of the legislation," they wrote.
"For instance, foreign companies could be listed on the London Stock Exchange, pay bribes and get away with it.
"This will disadvantage all honest companies and, perversely, turn on its head the government's stated aim of creating a level playing field through the Act’s extra-territorial reach."
George Boden, a campaigner at Global Witness, said question-marks about the SFO's future as an agency could "completely undermine" its pursuit of companies.
Several senior staff have already quit the agency as a result of speculation about its future.
Earlier this month home secretary Theresa May attempted to dismiss fears that the SFO might be folded into the coalition's broader National Crime Agency (NCA), however.
"We will review the relationship between the economic crime command and the other agencies in due course to ensure there is an effective working relationship between them," she wrote in a letter to the Bond anti-corruption group.
"However, I can assure you there is no intention to reduce either the resources or the priority given to tackling corruption."
She told the Commons that an economic crime command within the NCA would be set up which will assess how "better coordination among the agencies" can be achieved.
Mr Bayley said it was not clear whether the SFO will remain the prosecuting authority as well as the investigating one.
He added: "Under Richard Alderman's leadership, the SFO has started taking bribery cases through the courts. We need to keep a dedicated agency for investigating and prosecuting serious financial crimes."
Unconfirmed rumours suggest that the City of London police force could win the investigatory remit.
The SFO has said it expects it will only mount an additional 1.3 prosecutions a year as a result of the Bribery Act coming into force.