- Violent crime fell by 22%.
- Violent crimes against the person (excluding domestic violence) fell by 39%.
- There were 10 fewer admissions to hospital.
Such crude and imprecise statistics amount to disinformation, but I can foresee that they may provide an excuse for licensing authorities to impose a requirement to use breathalysers as a condition of granting new licenses or renewing existing ones. They'd thus be imposed upon us by stealth.
As for the level of 2.5 times the drink-drive level: it's impossible to be precise, but wouldn't that be around five pints? That's not exactly binge drinking, and it would definitely inhibit the great British tradition of pub crawls. Breathalysers are associated with breaking the law, and I'd expect them to irritate customers who'd not appreciate being treated like offenders.
Ultimately, though, it comes down to eroding personal freedom. Drinking is a legal activity; even being drunk isn't illegal as long as you're not disorderly. It's worse than the nanny state because the use of the breathalyser is not compulsory, at least not at present: we'd be foolish to sleepwalk into regulating ourselves when there is no legal requirement to do so, and where there are no genuinely quantifiable benefits.