One supposed obstacle to shifting taxes from output and employment to the rental value of land is that "turkeys don't vote for Xmas", which pre-supposes that a vast majority of the electorate derive more income (or benefit) from landownership than they do from going out to work or running a business (which is clearly nonsense).
While it is often stated that 68% of UK households are owner-occupiers (who by implication would rather go for the safety of government protected land values), Rob B asked me whether there are any statistics on how many adults are owner-occupiers (singly or jointly with partner).
For example, if there are two houses, one owned-occupied by a single adult and the other rented to a couple, that's 50% of households who are owner-occupiers, but only 33% of adults. So on a per-household basis, there is no majority for shifting taxes from output and employment to the rental value of land, but on a per-adult basis there is.
As far as I can see, there are no such statistics, but we can reverse engineer it from the DCLG's English Housing Survey for 2008-09 and the ONS survey Families and people in families (published early 2012, Excel Tables here).
Table 3 of the former lists each household by type and says what percentage are owner-occupiers or tenants in England; sheets 1 and 7 of the latter give the absolute number of each household by type for the UK. We can assume that the percentages for England apply across the UK and thus multiply them by the absolute number.
We can then multiply the number of owner-occupier households with only one adult (single, widowed or lone parent) by one and the number of owner-occupier households with two adults (couple) by two (and the number of 'other' households by 1.5) and we arrive at the grand total of 30.1 million adults who can describe themselves as owner-occupiers.
The total number of adults in the UK from the 2011 census (click the link under Figure 3) is 50.5 million.
30.1 million divided by 50.5 million is just under sixty per cent.
(Quick check: there are 18 million owner-occupier households in the UK, of which one-third are single, widowed or lone parent and the other 12 million are couples; 6 million plus 24 million = 30 million. Looks about right).
We could tweak that a bit in either direction, for example we could deduct a million owner-ocupier households who have little or no equity in their home, but that is then guesswork/subjective.