Where is it?
It's nowhere any more, swept away and removed completely when the A1 was upgraded to motorway between 2006 and 2009. A local service road running down to the A659 interchange to the south replaces this interchange.
When it still existed, it was the southern end of the notorious Wetherby Bypass, also connecting the A661 to the A1. It was a local junction despite the primary routes involved.
What's wrong with it?
It's a horrible mess of sliproads, roundabouts and tangled connections that make any movements (except going straight through on the A1) a headache. Even the simple flyover from the A58/A661 roundabout to the A1 south is complicated by a farm access road which means it ends in a roundabout and has a two-way flyover. The local road towards Walton is hijacked for the A1 southbound off-slip road and a local road through Wetherby is now used as a shortcut by some.
Why is it wrong?
It's a patchwork of previous junctions. Initially the A1 (as a single-carriageway road) had entered from the south and continued through Wetherby on what is now the A661 and B6164. It was bypassed with a new dual-carriageway which left the A58 roundabout and crossed the river and headed around the town. When the A1 was grade-separated here a bypass was built for the southern end of the bypass, making a new river crossing. The remnants of the old junction are visible where the sliproads from the A1 to the south join to form a small piece of dual carriageway to the roundabout, and the small section of the A58 east of the main roundabout crosses the river on a bridge which once held both carriageways of the A1, though one is now grassed over and looks rather silly (the too-wide bridge is visible on the aerial photo). None of this is helped by the fact that three lanes of traffic just off the brand new A1(M) is piled onto each end of the bypass.
What would be better?
It's easy to say "bulldozing the lot" as a solution, but this is in fact the plan! Since the A1 upgrade to motorway is now about to go ahead, Wetherby will at last get a new bypass and this junction will cease to be. A new junction with the A1224 further north (A1(M) J46) will serve Wetherby instead, and the 1950's bypass will finally stop having to take the strain of A1(M) traffic.
Right to reply
There is no defence for what was there before.
Happily, the new junction is taking shape nicely, and the new Service Station is a bonus!
The immediate problem with the new junction is that it is quite some distance away from Wetherby. Perhaps it may have been nice if the A58 actually now reached the A1(M) rather than dying arbitarily on the local access road...
At least, for now, it all works well. I do worry that the local access road will become busier and busier over time.