The Duke of York has become the first member of the Royal Family to join Twitter under their own name.
Andrew's Twitter membership was launched with the simple tweet "Welcome to my Twitter account - AY".
Tweets signed AY, for Andrew York, are personally written by the Duke while others will be posted by his office.
But already his account - @TheDukeOfYork - has attracted unfavourable comments.
One person tweeted "yo how's Jeffrey Epstein?", referring to the Duke's relationship with an American billionaire who was sentenced to 18 months in prison in 2008 for soliciting a minor for prostitution. Another posed the question "Has your account been hacked by Ali G?", but Andrew also received messages of welcome from the online community.
The Queen and members of her family are represented on Twitter by the account @BritishMonarchy, while @ClarenceHouse covers the Prince of Wales, Duchess of Cornwall, Duke and Duchess of Cambridge and Prince Harry.
A spokesman for Andrew said: "The Duke has long been an early and enthusiastic adopter of new technology. He was in fact the first member of the British Royal Family to tweet on the British Monarchy (account) when he visited Tech City. The logical next step was to tweet individually."
Asked about the derogatory tweets Andrew has received, the spokesman added: "The Duke is a champion of free speech, for him it's about telling people what he's doing."
Andrew's Twitter account already has more than 5,000 followers and he is following 42 other users of the micro-blogging website.
Accounts being monitored by the Duke include entrepreneur Peter Jones, the BBC Dragons' Den star, Seamen's Hospital Society and Hunstanton Golf Club.