1) Go ahead with the published scheme (2.1km bored tunnel from King Barrow Ridge to Airman Crossroads)

or

2) Do nothing

The north and south routes are nonsense, put about as a desperate attempt to find 'cheaper' solutions than the tunnel itself.

Both routes would obliterate huge areas of the World Heritage Site.

The northern route would cut Stonehenge off from its wider context (Durrington Walls / Woodhenge etc).

The southern route would cut Stonehenge off from the other side of its environs - the Lake Group barrows, particularly.

Both are the antithesis of what the strategic plan for the WHS calls for - to restore Stonehenge in its original context as part of a unified mesolithic/neolithic/Bronze age landscape.

One option I've heard mentioned is to close the A303 across the WHS entirely and make a fast route to the south west along the A30 route instead.

--
simon