As a lifetime senator, Mr Monti cannot run for office but can takepartin an election campaign and can return to the post of prime minister if asked by aparty or coalition.
Prof Bogdanor told Today presenter James Naughtie that retired members of the armed service "have every right to takepartin the political debate, " but added that former personnel "must not appear to align themselves with a political party, " particularly in the build up to a general election.