Six friends P, Q, R, S, T and U are sitting around a hexagonal table, each at…

Concept: In a circular or polygonal seating arrangement where everyone faces the centre, 'left' and 'right' are two fixed, opposite rotational directions around the ring. Once one clue fixes which direction is 'left', every other '...to the left/right of...' clue must be read in that same direction, and 'A is nth to the left of B' places A exactly n seats from B along it.

Application:

1. Since P is second to the left of U, moving two seats in the left direction from U lands on P - there is exactly one seat between U and P in that direction.

2. Q is a neighbour of both R and S, so R and S occupy the two seats immediately next to Q, one on each side.

3. Since T is second to the left of S, moving two seats in the left direction from S lands on T.

4. With only six seats available, these three clues fix one unique order in the left direction: P, R, Q, S, U, T (and back to P) - it satisfies U-to-P in two steps, R and S flanking Q, and S-to-T in two steps, all at once.

5. Counting four seats in the left direction starting from Q: first S, second U, third T, fourth P.

Cross-check: the table has six seats, so the fourth seat to the left of Q is the same seat as the second seat to the right of Q. Moving two seats in the right (opposite) direction from Q - through R - also arrives at P, confirming the result.

Therefore, P is the fourth person to the left of Q.