"I intend to defend this claim vigorously and to issue a counterclaim as appropriate," said Judge, a one-time Cadbury Schweppes executive, former director general of Britain's Conservative Party and a well-known figure in the City of London.

"If ENRC persists in the legal action then I look forward to the day when the High Court examines the full factual background to ENRC, its directors, shareholders and this misconceived claim," he said in statement over the weekend.

He said documents lodged with the court contained only one allegation of a leak to the media, and he denied involvement.

Judge served as a director of troubled miner ENRC from 2007, when the group listed in London, until June this year.

ENRC - currently in the throes of a buyout by a trio of co-founders that will end five turbulent years as a public company - has been plagued by bitter boardroom battles, whistleblower allegations of graft and, since April, an official probe into claims of fraud, bribery and corruption.

(Reporting by Clara Ferreira-Marques; Editing by Louise Heavens)