Downing Street has refused to say whether key messages between Morgan McSweeney and Lord Mandelson have been lost after it emerged that McSweeney's government phone was stolen last year. The government has promised to comply with a demand from MPs to publish all messages relating to the appointment of Lord Mandelson as US ambassador despite his friendship with convicted sex offender Jeffrey Epstein. Asked if that would all include all of McSweeney's messages, the PM's spokesman said he would not comment on the "contents of the second tranche of documents". The first set of documents, which reveal the PM was warned about the risk of appointing Mandelson, were released earlier this month. Messages from ministers and government aides are expected to be included in the second release, raising questions about whether information held on McSweeney's stolen phone would be accessible. His messages are seen as crucial because he pushed for Lord Mandelson's appointment to the role in Washington.…