The father of Simone Zaza admits his son made a massive mistake by joining West Ham last summer, blaming the British weather and Slaven Bilic's tactics for the striker's miserable stay.

The Italian international joined the Hammers last summer on a season-long loan from Juventus following Euro 2016, where he found infamy for his awful penalty miss against Germany in the quarter-finals.

His fortunes in London were no better, as he played 11 times in all competitions under Bilic, failing to register a single goal before his short-term deal was terminated in January 2017.

Simone Zaza's father insists his son made a huge mistake by joining West Ham on loan last year

He spent the second half of the season on loan at Valencia, which has now been made permanent following an impressive return to form, and his father Antonio, who also works as the striker's agent, believes a break from the miserable London forecast and Bilic has worked wonders for his son.

'It was a huge mistake,' Antonio told Calcio Mercato when asked about his move to the London Stadium.

'Simone was still concerned by the penalty he missed with Italy at the time and he failed to settle in well in London.

'He was not happy with the weather and with the formation of his ex-boss. Moving to Spain was the best ever decision for him.'

Zaza and Valencia have enjoyed an incredible start to the season in La Liga, with Marcelino's side still unbeaten and the Italian striker bagging six goals in his first seven appearance in the league.

The Italian striker has returned to seriously impressive form with Valencia in Spain this season

Despite his remarkable record, Gian Piero Ventura has decided against calling up the 26-year-old for Italy's final two World Cup qualifiers, and Antonio admits his son has been stung by the decision, and hopes his mistake at Euro 2016 won't count against him in the future.

'We respect the choices of Ventura,' he said. 'Of course Simone was not happy for the decision because things are going well in Valencia at the moment, every player dreams of the national team.

'Only who takes the penalties miss them. When he took the responsibility he knew he could fail. I hope no (that the miss will count against him), anyway. He did many positive games with Italy.'