This was a lot easier to find than I was expecting. Take the turning into Upper Lambourn off the B4000 at the junction where the cemetery is. You shortly come to a T-Junction – turn right (sign posted dead end) and follow the narrow lane up the hill to the left until you reach the cross roads and the lane in front of you turns to dirt. Park as best you can and walk up the dirt track. Shortly the track splits – take the left hand track. The stone is on your right hand side about 100 metres up the lane. The stone is about 1.5 metres high and about 0.5 metres wide at the bottom – tapering towards the top. The lane is narrow and has overhanging trees on both sides. I can well imagine children in the village daring each other to visit the stone at night! It would be quite scary in those circumstances although it was very pleasant in the summer sunshine when I visited.
From White Horse Hill and Surrounding Country by L V Grinsell.
'There is another Hangmanstone, 4+1/2 feet high, south of the Lambourn Seven Barrows, and many others exist in southern England, some being connected with a legend of a man whoe stole sheep and rested at the stone with the sheep tied by a cord; but in its efforts to get away the sheep twisted the cord round the man's neck and strangled him. This legend has not, however, been recorded of the Berkshire stones, so far as I know.'
Compare with som text from; Memories of Old Berkshire, by Jane M Taylor O.B.E.
'By the side of a lonely road near where we lived is a very large, rather flat stone, known locally as 'Hangman Stone'. The story is that a man stole a sheep, tied it by the legs and hung it around his neck to carry it home. He grew tired, and sat down on the stone to rest. The sheep struggled and the cord hanged the man; and to this day that road is called Hangman Stone Lane, and it is still haunted by the ghost of the sheep stealer.'
[SU 3200 8117] Hangman's Stone [G.T.] (1) Hangman's Stone, Lambourn. A naturally shaped, grey upright sarsen stone, set in a bank on the east side of a lane and standing four feet above it. No sign of mound or any other sarsens, in the vicinity. (2) Hangman's Stone, see G.P. AO/63/95/1. (3) Additional bibliography. (4)