At least in the case of Italy, no. This was not a possibility the previous governments (including the Fascist one) had even taken into consideration, and the country was actually stripped of most of its colonies - with the partial exception of Somalia - at the end of WW2. But even there it was the UN which set forth a road-map for the former colonial power to follow; Italy was allowed to keep administrating the former Italian Somaliland as a Trust Territory until it was to be merged with British Somaliland and granted independence... something that happened on the 1st of July, 1960.