Tuffi (Pte) Ltd v Techkon Pte Ltd & Anor

Contract — Mistake — Mistake of fact — Whether mistake attributable to fault of a party; Evidence — Witnesses — Competency — How witness with speech impediments may give evidence; Contract — Contractual terms — Implied terms — Whether implied term for adjusting sum payable exists; Restitution — Mistake — Mistake of fact — Whether mistaken payment or mistake in formation of contract; Contract — Privity of contract — Whether joint venture company also party to agreement between principals; Contract — Contractual terms — Interpretation — Whether parties agreed on fixed sum or formula for payment