The reliability of the ZX81 was controversial. W.H. Smith, one of the machine's key distributors, had a company policy of ordering a third more ZX81s than were actually required for sale, so that it would have enough replacements for faulty machines. Similar problems were reported in the US market, where contemporary reports suggested that only a third of the ZX81s shipped actually worked. However, figures released by Sinclair claimed that only 2.4 per cent of pre-assembled machines were returned, although 13 per cent of kits were returned. Clive Sinclair strongly denied any problem with reliability: