The PEGI 18 rating will not be legally enforceable until 1st April 2011, the Video Standards Council said.
In the meantime, publishers must continue submitting games that receive PEGI 18 ratings to the BBFC for certification.
"The Digital Economy Act has been passed in the UK but has not yet been made effective," the VSC explained in a statement carried by MCV.
"The Government has said the legislative change is likely to be implemented on 1st April 2011."
Last month VSC director general Laurie Hall said that the changeover was waiting on the Secretary of State to get his various legislative ducks in a row.
"There are various arrangements that have to be put in place: a statutory instrument for dealing with packaging regulations; the Secretary of State has to be happy that the arrangements that the VSC itself has put in place to carry out its statutory duties are in order before he designates us," Hall told Eurogamer TV in the second episode of our series, The Videogames Election, which you can watch below.
The decision to make PEGI ratings legally enforceable was taken under advice from the 2008 Byron Review.