There doesn't seem to have been an official announcement, or if there was then we missed it, but it appears that the government's new social-distancing rules allowing the two-metre rule to be reduced to "one metre plus" in certain circumstances do apply to buses.
Nor have our local bus companies exactly gone overboard to bring us this good news. Buried away in the "Coronavirus" pages of Stagecoach's website, but with no indication on the link that anything has changed and that it might be worth looking at them again, is the new Guidance on socially-distanced travel by bus.
To save you the trouble of trying to find it, here it is - best summed up by this poster
With one passenger allowed to occupy EVERY double seat (and more if travelling as a household or bubble) the carrying capacity of the bus is increased from 25% to 50%, meaning there is much less risk of passengers being left behind by a "full" bus.
More detailled information is available on this poster, although you'll have to forgive the trainee at Stagecoach who was given the job of writing it for his or her grammar (it should of course read fewer available seats)
Now that we've found it, we are very pleased to see this news from Stagecoach and we hope that those newly-available seats will soon by filled with happy bus travellers.
Co-incidence?
It might, of course, be just a co-incidence but only last week the Bus Users' Group supported a joint approach to the Secretary of State for Transport by six leading public transport organisations asking him to change the message on public transport and to stop the damaging "avoid public transport" mantra that was doing incalculable long-term harm to the industry. It would seem that, for once, someone was listening.