The Planning Portal recently published the following guidance: "Where possible, separate plans and drawings on to different sheets with a single scale, and with a preference for A3 sheet size or smaller if possible".  The article was mainly concerned with achieving paperless submission of planning applications and included this lovely comment:

"It is my belief that after 10 years of driving this particular horse to water, it should know not only know the way by now, but it should have a capuccino machine installed."

This is the response we added to the PP page:

It is very helpful that PP has raised this issue. Most developments can be communicated in A3 format with a little forward planning and a good figure naming/numbering system.  There is always an issue of exact scale with PDFs and their margins.  Stated scales are should be taken as indicative (that is probably all they need to be) but a barscale will enable acceptable dimensions to be taken by anybody with a few brains cells to rub together. On larger maps, a 1km grid (or as suits the map scale) is more useful in establishing sense of scale and distance than a set of numbers.
 
A3 format works very well for paper and screen.  My 24" (diagonal) screen comfortably displays A3 landscape drawings at the correct size (16.5 x 11.75" in old money), with about 4"/100mm space to one side. Fullscreen mode (quite often F11 in PDF viewers and browsers) comes close to the experience of looking at the original A3 sheet, accepting the compromise of screen resolution relative to print resolution. And of course an A3(L) print can be folded neatly into an A4 report when required (eg for public inquiry, which is anything but paperless!).  I know not everyone has a 24" monitor, but a quick search found the cheapest 24" monitor (on a website named after a rainforest) is £120 - not exactly elitist.
 
I am regularly surprised at how poorly technology is used by many people. One of our products is photomontage and if submitted electronically, the only processing is from the graphics software (say PhotoShop/CorelDraw) to PDF, giving a 300dpi image with a reasonably small amount of compression.  If an LPA insists on paper, the process to get it in front of a stakeholder/decision maker is [Graphics software > PDF > laser/inkjet printer > scanner > PDF] - each arrow represents a process where quality is likely to be lost. In the case of detailed photomontages, this can be disastrous - but probably less so for line drawings of building elevations.
 
So quite right, the horse should be drinking cappuccino by now!