Yes, if your period of occupation amounts to residence.
Unfortunately, the legislation does not provide for any minimum period of occupation to qualify for Main Residence Exemption. The Courts have stated that it is "quality not quantity" that is important.
IMHO, the IR are unlikely to challenge the exemption if you have lived in the property for over 1 year - 3 months is likely to be too short, although it would depend on the circumstances.
Have you read the Inland Revenue's Help Sheet IR283 which deals with CGT for private residences?
It is downloadable from their website.
http://www.hmrc.gov.uk/leaflets/menu.htm
[CAVEAT : see Matthew Hutton's article of August 2005 where Lettings Relief falls within last 3 years of ownership :
http://www.taxationweb.co.uk/articles/a ... php?id=215