Using a filter lane the wrong way

[TimewarpUK]

Near me there's a busy single-carriageway A road with a turn off onto a fairly busy minor road (one way).

Because several vehicles are often queuing to turn right, there is a filter lane in the middle for right turning traffic, with a section labeled "Keep Clear" because there is a track to a farm entrance on the other side. The filter lane has an arrow bending to the right, showing that it is there for turn-in into the minor road (although I know arrows are advisory and are not something that road traffic regulations would dictate that MUST be followed).

Now there's a guy I see quite often using this filter lane the wrong way to turn into the farm track. Imo this is fairly dangerous, as he often meets traffic preparing for the right turn in the filter lane, and they have to suddenly stop, not expecting oncoming traffic to be in this lane.

Now what is the legality here? If it were me I'd stay on the left of the filter lane if turning right into the farm track, making use of the "Keep Clear" section if somebody let me in, otherwise I'd stay put waiting for oncoming traffic in the main carriageway and filter lane to be clear, albeit at the expense of blocking traffic behind me.

Is this guy doing anything illegal using the filter lane the "wrong" way?

[Monty Python]

Try contacting the appropriate police force - I've done this for a few things and usually get quite a good response from them.