In the United Kingdom, a hybrid bill is a public bill which affects the private interests of a particular person or organization. It is generally initiated by the Government on behalf of non-Parliamentary bodies such as local authorities and is treated like a private bill for the beginning of its passage through Parliament. This gives individuals and bodies an opportunity to oppose the bill or to seek its amendment before a Select Committee in either or in both Houses. The bill is then treated as a public bill.
Examples of hybrid bills have been those to construct the Channel Tunnel, the Dartford-Thurrock crossing (also known as the Dartford Crossing), the London Passenger Transport Board and Crossrail.
The use of hybrid bills originated as part of the parliamentary procedure of the United Kingdom Parliament, but the procedure is also occasionally used by overseas parliaments and assemblies set up on similar lines to that of Westminster.
Historically, hybrid bills have often been used by the Government on behalf of railway companies and transport agencies to obtain authorisation for major projects deemed to be in the national interest, but which would affect a large number of private interests.
Statutory instruments can also be hybrids. When opposed, such instruments are referred to the Hybrid Instruments Committee to report to the House on whether a select committee should be appointed to consider the petition or petitions against the instrument.
In Canada, they are specifically disallowed by Beauchesne's Rules and Forms of the House of Commons of Canada, which states that "According to Canadian standing orders and practice, there are only two kinds of bills - public and private. The British hybrid bill is not recognized in Canadian practice."