Guernsey’s Chief Minister, Deputy Gavin St Pier is writing to Boris Johnson to congratulate him on his successful election as leader of the Conservative Party and Prime Minister for the United Kingdom.
Mr Johnson was running against Tory leadership hopeful Jeremy Hunt during the six-week long campaign.
The former Foreign Secretary was widely expected to be crowned the next leader and was a clear front runner throughout the contest.
The Conservative party's 160,000 members chose the new leader via a postal ballot, in which they had a month to decide their next leader.
Mrs May will tender her resignation to the Queen after taking Prime Minister's Questions in the Commons on Wednesday afternoon for the final time, with Mr Johnson set to enter Number 10 soon afterwards.