Being one of the first solicitors to concentrate on Trade Unions, Roberts was appointed as the legal adviser for the
Northumberland and
Durham Miners' Union. He became popularly known as the miners' "attorney-general". His philosophy was simple:
"We resist every individual act of oppression, even in cases we were sure of losing." Roberts challenged the
Bond, the oppressive terms of employment under which the miners worked. He won many legal battles against the
Bond and gained notoriety for securing the release of pitmen from
Thornley, Durham colliery in 1843, who had been imprisoned for breaking the
Bond. He also attacked the
Truck system in which miners were paid by kind rather than cash.
Friedrich Engels described this as a "Crusade against despotic Justices of Peace and truck masters". Roberts held an inquest into the
Haswell colliery explosion, September 1844, in which 95 miners lost their lives. His accounts led to a government inquiry into mine safety. During his time as a legal adviser to the mining union he edited the ''Miners' Monthly Magazine
between March–July 1844. "In making this arrangement, Mr R's principle motive is to give an opportunity to the pitmen in that neighbourhood of consulting him without their having the trouble of coming to Newcastle."'' He also contributed to the union journal, the Miners' Journal which later was named the ''Miners' Advocate''. ==Manchester==