This has not actually been tested in Court yet to my knowledge. However, there are no limits on how far back a Local Authority may go to ascertain gifts which have as their "signficant" reason the defeat of a contribution to care home fees. A younger person, who has no reasonably foreseeable need for long term care may well get away with it. However, there is almost unimited powers for the LA to look into your past. If it is deemed that you have given away your asset to defeat a contribution to care fees, then the LA deem you to have capital to the value of the asset, decreasing on an annual basis by the fees that you are deemed to have paid. This will be secured by a charge on the property (most people end up entering into a deferred payment agreement to charge the property with the fees).
More info here:
http://www.dh.gov.uk/en/Publicationsandstatist ics/Publications/PublicationsPolicyAndGuidance /DH_4107292
The 7 year rule has no bearing on care home fees - this relates to inheritance tax, whereby if you give an asset away and survive 7 years it is not brought into account for IHT.
Thus you end up with the anomoly that if you gave your house away and survive 10 years, it is not taken into account for IHT, but may be taken into account for care home fees.