No plates=/=untaxed. Councils do not have power to remove untaxed vehicles, DVLA would have to do it (they won't).
Your vehicle may also be removed if:
it is considered to be abandoned
it is untaxed
From .gov.uk Decide if a vehicle is abandoned Authorities must decide if a vehicle is abandoned. This is likely if at least one of the following applies:
it has no keeper on DVLA’s database and is untaxed - check vehicle tax online it’s stationary for a significant amount of time it’s significantly damaged, run down or unroadworthy, for example has flat tyres, missing wheels or broken windows it’s burned out a number plate is missing They can legally enter land (at a reasonable time) to investigate and remove abandoned vehicles