Answer the following problem based on R v Gibson [1991] 1 All ER 439. You need rely only on this case and the statutory provisions in it; it is not required or necessary that you do any other reading.

The British Museum has put on display a classical vase from Ancient Greece. The vase has recently been excavated and has been purchased by the Museum using funds provided by the Culture Ministry as well as donations from the public. However, when the vase was put on display, the museum received a number of complaints. These complaints were caused by the fact that the vase depicted scenes of both heterosexual and homosexual sex. The museum is concerned about the legal implications of the display of the vase. Advise the museum as to whether the vase might be considered in law to be obscene and, if so, whether they can rely on the defence contained in s.4 of the Obscene Publications Act 1959.