According to the Chartered Institute of Taxation, the government are really keen to get tax payers, or rather those who aren't paying what they should be, 'working' more for HMRC.
In a consultation exercise, the government is proposing a Contractual Disclosure Facility where HMRC would offer those suspected of tax fraud the opportunity to enter into a contract to disclose that fraud in exchange for a guarantee that they will not face criminal prosecution.
This would apply only to cases where HMRC believe that criminal investigation is not in the public interest nor the most cost effective way to tackle the suspected fraud. The 'contract' would be arranged under HMRC's Civil Investigation of Fraud Procedure.
There is a gotcha though. Anyone entering into such a contract needs to be fully aware that where they fail to comply with the contract, for example by procrastinating or not making a full disclosure, they will potentially face cancellation of the agreement and, in the worst cases, criminal action.