According to the Policing and Crime Act 2009, for violence to be ‘gang-related’ means that it involves at least three people, associated with a particular geographical area, who have ‘a name, emblem or colour’ which allows others to identify them as a group. Last month this was revised in new statutory guidance from the Home Office. There’s no longer any mention of geographical territory or gang emblems: a ‘gang’ is any group that commits crime and has ‘one or more characteristics that enable its members to be identified as a group’. There’s no mention of what those ‘characteristics’ might be.

The whereabouts of Ibrahim Magag are causing concern. The 28-year-old hasn’t been seen at home since Boxing Day, and though that might ordinarily be the business of no one but his wife and kids, his absence has set off a police manhunt and exposed him to the risk of five years in jail. Magag isn’t a defendant awaiting trial or a convict due to be sentenced. His brush with the law has arisen because he is one of ten people on whom the home secretary, Theresa May, has served a notice under the Terrorism Prevention and Investigation Measures Act 2011. Although it is impossible to be sure what the TPIM notice said – its contents are not a matter of public record – it seems to have asserted May's belief that Magag, who was born in Somalia, was linked to the extremist organisation al-Shabaab. That belief entitled her to impose restrictions on his liberty, including a curfew, and he is a fugitive only because of his apparent breach of those restrictions. In other words, Magag stands to be criminalised because the home secretary suspects him of criminality.

What’s the difference between Martha Stewart, ‘lifestyle guru’, ‘third most powerful woman in America’ etc, who was refused entry into the UK last year, and the 16 foreigners who have just been barred by the Home Office? Jacqui Smith’s initiative – name the naughties – was announced on Tuesday, with some fanfare and much triumphalism. It fingers people likely to stir up hatred or ‘glorify terrorist violence’, which obviously isn’t Stewart’s bag, and not all of them have criminal records, which obviously is, yet somewhere here there’s a bigger difference. It was about this time last year that Stewart was planning a visit to Britain but a few days before she was due to jet in, she was told she couldn't come. Her criminal past in the US was the problem. She wasn't convicted of insider trading, but she did fib to investigators during an inquiry into the sale of shares in the cancer-drug company ImClone hours before the public announcement that its wonder therapy, Erbitux, had failed to win FDA approval. That was in 2001; Stewart offloaded more than $200,000 worth of shares. In 2004 she was sentenced to five months in jail, which she served, coming out under supervised release in 2005. She famously told Barbara Walters that she wasn’t the only irreproachable human being in history to be sent down: ‘Look at Nelson Mandela.’