As a columnist, Tai was a relentless critic of Nigerian military rule, as well as of corruption in the government and the church.
For as the power of corporations expanded across the years, Ralph Nader's place as their most relentless critic grew too.
He was a relentless critic of the Labour Government's policy of nationalisation and the retreat from Empire.
Kusher became a relentless critic of the treatment of breast cancer by the medical profession.
She became a caustic and relentless critic of the Clintons.
These Pigs on the Face of the Earth: Israel's most relentless critic.
There was a time when Mr. Giuliani was a relentless critic of the city school system.
By far his biggest impact on the world scene has been to emerge as the most vocal and relentless critic of the Bush administration's march to war against Iraq.
To be sure, they are probably the governor's most relentless critics - in part because she has cast herself as an ally.
As ever, he is out to hush his most relentless critic, that hanging judge of his within.