Judge Robert Altham jailed Simon Blevins, 26, Richard Roberts, 36, and Richard Loizou, 31, over their demonstration at a Cuadrilla site.

The trio, known as the Fracking Three, are believed to be the first environmental activists to be imprisoned for public nuisance since 1932.

Critics have claimed the punishment was manifestly excessive. Now the Daily Mirror can reveal the Altham family business supplies the Irish Sea oil and gas industry.

J.C. Altham and Sons is believed to be part of the supply chain for energy giant Centrica, which has invested tens of millions of pounds in fracking.

Judge Althams sister, Jane Watson, put her name to an open letter in favour of fracking, which said, Its time to give shale a chance and claimed it would create jobs.

The judicial code of conduct states a judges impartiality may be questioned if family members are politically active or have financial interest in the outcome of a case.

Lawyers for the protesters are trying to overturn their sentences. Loizous mum Sharron, 62, told the Mirror: I was completely shocked when he was jailed, the sentence is incredi...