There is no official and distinctive email address that you can send emails to, but you can send a web-email to 10 Downing Street via the 'email' page of their website (see Related links below)
You can also write to or fax this official residence of the Prime Minister of The United Kingdom.
Full details are on the Number10 website. (see Related links)
You can also register there to go on their emailing list, and they will then send you regular updates and notices of any changes to their contact arrangements.
See the link below
10 Downing Street is the official home of the British Prime Minister.
There is no number 20 in Downing Street but the Prime Minister lives at 10 Downing Street.
10 Downing Street, home to the Prime Minister.
The complete address for the home of the First Lord of the Treasury/British Prime Minister is:10 Downing StreetLondon SW1A 2AA, United Kingdom
10 Downing Street, London
10 Downing Street
10 Downing street
10downingstreet@hotmail.co.uk
10 = Downing Street (Residence of the British Prime Minister)
10 downing street
10 Downing Street London
No 10 Downing street