Sporting president Bruno de Carvalho referred to West Ham owners David Sullivan and David Gold as the with a derogatory term on Wednesday in an interview with Sporting TV, according to Portuguese newspaper Record.

The Hammers' proposed £23 million deal for the Portugal midfielder broke down before the transfer window closed last week.

Sporting claimed West Ham had never submitted an official bid for Carvalho, leading the Hammers to vow to sue the Portuguese club.

And now Sporting director De Carvalho has hit out at Sullivan and Gold, while Sky Sports News claimed to have obtained emails that prove West Ham did indeed bid for Portugal star Carvalho.

"Instead of spouting off, West Ham's offer should be shown. Where is it? What proof is there,'' De Carvalho said on Sporting TV. "What has happened here? The chairman [Sullivan] is very happy with the coach [Slaven Bilic], who was the person who wanted William.

"The man wanted to give the coach the player he wanted as much as I want to give a Christmas gift to my enemy. I did not want to give you anything!

Carvalho's explosive season in Portugal has put him on various clubs' transfer radars. Miguel Riopa/AFP/Getty Images

"West Ham supporters call Mr David Sullivan and his brother the dildo brothers.''

Sullivan and Gold are not related but are long-standing business partners.

Sporting's latest derogatory remarks aimed at West Ham follow their communications director accusing Sullivan of being a "liar'' and "parasite'' in a Facebook post.

No sooner had Sporting director De Carvalho called out West Ham to produce proof of their offer on Wednesday though, than Sky Sports obtained emails apparently showing precisely that.

The emails Sky Sports published detail an offer of €25 million to be paid in three instalments across 24 months for the 25-year-old.

West Ham have previously confirmed their intention to launch legal action against Sporting for claiming the Premier League club did not submit any transfer offer for Carvalho.

Writing via his personal Twitter account on Sunday, owner's son David Sullivan Junior said: "West Ham are commencing legal proceedings against the communications director of Sporting Lisbon as a written offer for the player was made.

"To Bruno de Carvalho the president of Sporting Lisbon. To say we never made an offer is nonsense and serious libel.''