The big potential spreader is the London Underground; closing that down, even for a day or two, would be huge.
*If* it came to that sort of level it surely shouldn't be beyond our resources as a country to provide hand gel and face mask booths at all (major) underground stations (maybe closing minor ones)? (No one allowed on underground unless they use the gel and wear the mask; the mask is to protect *others*, not yourself, but that works if everyone wears one).
The *official* worst case scenario for the UK was released as 80% infection rate, 500,000 dead. It probably won't be nearly as bad as that, it was a very worst case, and quarantine measures might reduce the rate, but the figures I've seen indicate it is 5-7x more deadly than 'normal' flu. But 'normal flu' does have some at least semi-effective** vaccines for vulnerable people and medical staff.
As I'm quite old and not in the best of health, personally I'm quite concerned. I'm retired so luckily I have the choice to stay away from crowds (and particularly London Underground or similar).
If you're younger and fitter than me you almost certainly have nothing to fear personally, and even small children don't seem to be seriously affected - but if it does get widespread please think about whether you could be spreading it to the old, ill and immuno-compromised.
I'm trying not to be alarmist*; SARS and MERS and Ebola were/are all much more *deadly*, it's just that COV19 seems to be much more *infectious*,cases are popping up with no obvious origin/contact whereas SARS/MERS etc. didn't spread as widely/qucikly - there seems to be quite a long period where people are carrying it but not showing symptoms.
Anyhow, trying to be more constructive, the medical advice seems to be that the most significant transmission vector is *not* airborne, but by touching surfaces and then touching the eye, and that as a result frequent hand-washing plus avoiding skin contact with handles etc. (as opposed to masks) is the most effective way of preventing transmission. A simple thing like using the knuckle instead of the finger pad to open a train door would break the door button->finger pad->eye transmission route.
* Given that the government has mentioned the *possibility* of (e.g.) closing schools for two months, and a *worst case* of 500,000 dead, 80% infected, I think we have to consider 'serious' scenarios and it's not really alarmist to do so.
**Varies by year/strain.
Mods please delete this if you think it's OTT or inappropriate; I've tried to keep it somewhat related to the railway issue.