The BPA joined a nationwide campaign against ritualism within the anglican church, affiliating to the Imperial Protestant Federation, a network of ultra-protestant societies. The Rev. William Peoples, newly appointed Church of Ireland minister of St Clement's church in east Belfast, who mistakenly thought the anglo-catholic ritualism which appealed to slum-dwellers in east London would prove equally popular in Belfast, had his services disrupted and was forced to leave Belfast. Such violent breaches of public order contributed to a sense among ‘respectable’ unionists of the BPA's disreputability, as did its prurient oratory on alleged historical and current clerical sexual misdemeanours.
Like John Kensit (1853–1902) in England, Trew extended his campaign from attacking anglican ritualism to attempting to suppress such public expressions of catholicism as religious processions. In June 1901 Trew was jailed for a year for disrupting a eucharistic procession; he was released on 18 July, the day after the death of William Johnston (qv), MP for Belfast South. Trew sought the support of the BPA to stand as an independent candidate but was rejected in favour of T. H. Sloan (qv). Although Trew campaigned for Sloan, the BPA split immediately after the election, owing to personal rivalries between Trew and Sloan. Their competing meetings at the Custom House led to violent clashes, including fist fights and at least one stabbing. During subsequent legal proceedings it was alleged that Trew was supported by the Bogey Crowd and another gang, the Forty Thieves.
Trew aligned himself with the official unionist party and campaigned against Sloan in subsequent elections; after the loss of the Belfast West parliamentary seat to the nationalist Joseph Devlin (qv) at the 1906 general election (through a suspected electoral pact with Sloan and the intervention of a vote-splitting liberal unionist, Alexander Carlisle (qv)), Trew led a mob of Shankill Road protestants who stoned the Sandy Row Independent Orange Hall and burned Carlisle in effigy. Trew spoke against the 1907 Belfast strike led by James Larkin (qv), whom he described as a blackleg; after fleeing a Larkinite attack at the Steps, Trew briefly confined himself to criticising police brutality against strikers, reverting to denouncing Larkin after publicly expressed separatist support for the strike lent plausibility to his earlier claims that it was a nationalist Trojan horse. Trew campaigned for Sloan's successful official unionist opponent in January 1910 and took part in the subsequent campaign against the third home rule bill, though his later activities have not been researched in any depth. In July 1913 he led a gang of his supporters to Castledawson, Co. Londonderry, where they wrecked an AOH hall and several catholic homes in retaliation for an attack on a Sunday-school excursion by catholics in July 1912. He disrupted an anti-conscription meeting at the Belfast Custom House on 14 April 1918, and after this disappears from the historical record.