This whole working from home thing is an accident waiting to happen
Currently working from home is working out very well for employers since it frees up their own fixed resources (office space &tc.) and also guarantees that employees are effectively available 24/7. Freebe on-site technical support is just a bonus. This is all likely to change, though.
The catylist is in-home businesses. The line between 'hobby' and 'business' has always been a bit fuzzy but it really comes down to whether the hobby impacts the neighborhood and whether it makes any money. Office work at home doesn't impact the neighbors like car repairs or furniture making might but it could be said to be making money. This in the US tends to attract the attention of authorities, be it a zoning variance or business license or a more expensive 'business' network connection. The one person who won't be able to cash in will be the employee --- the rules were changed years ago to prevent people from easily writing off space in the house used for work, for example. (This is US practice but I expect that the UK won't be that different.)
Its only a matter of time before someone starts looking at working from home as "transferring a part of the business to a residential address". It'll be interesting to see how this pans out.