Some forces have defended their use of social media, saying that it helps them to keep in touch with the public, particularly young people. Police are encouraged to use such sites to "engage" with residents, post updates about crimes and appeal for information and witnesses. The majority of police forces have a main Twitter account, with many employing dedicated social media staff. Guidance from the Association of Chief Police Officers (Acpo) says that "the use of social media for private purposes during working time and from force systems should be in accordance with local force policies. Police Scotland, which last month said it was reviewing its Twitter use after an insulting message was posted from its official account, "follows" Andy Murray, the tennis player, and President Barack Obama. The force has apologised for the message, which was aimed at Toby Young, the Telegraph blogger, after he appeared on Newsnight discussing whether police should act to stop Twitter "trolls." Police in Solihull in the West Midlands follow Cricket Australia, which offers "all the latest breaking Aussie cricket news" as well as Danny Baker, the BBC broadcaster. Leicestershire Police follows Coleen Rooney, the wife of the England footballer, and Miranda Hart. Police in Lambeth, south London, followed Rihanna, Simon Cowell, Downton Abbey, Victoria's Secret, Christian Louboutin and Justin Bieber, the pop star, until the account was the subject of a complaint. A spokesman for the Metropolitan Police said: "Guidance is issued to police and staff authorised to use the MPS social media accounts and this includes following appropriate users on Twitter." It added that the officers who control the Lambeth account had been asked to review their usage and "make appropriate changes." Other forces said they were happy to have their officers follow celebrities. Staffordshire Police, which follows Rebecca Adlington, the swimmer, and a satire of Kim Jong-un, the North Korean leader, claims that it had gained the help of a celebrity in a police appeal, which it said was "very successful." Gordon Scobbie, formerly the Acpo officer responsible for social media, said: "I can understand following some politicians, celebrities with a cause, or perhaps local celebrities, but not Rihanna and Justin Bieber. Where forces are getting themselves into a bit of trouble is where they just go into it without thinking and letting a few people loose on it.