LILLE, France (Reuters) - A P&O ferry with more than 300 people on board which had run aground in Calais harbor in northern France has been refloated and all passengers have disembarked, a P&O Ferries spokesman said on Sunday.  The Dover-bound  Pride of Kent  had run aground on a sand bank around midday as she tried to leave the Calais harbor in stormy weather. Nobody was injured.  The ship, supported by two tug boats, was refloated as the tide came in early evening and all passengers have disembarked. The spokesman said most passengers would continue their journey to the UK on other P&O ferries tonight, while some would stay overnight in Calais on P&O s expense. UK-based P&O operates 20 ferries which carry nine million passengers per year between France, Belgium, The Netherlands and across the Irish Sea. 