Born at Sandwich, Kent, the son of Simon and Margaret Lowe (or Low), he entered the
During his time as a missioner he had known Anne Line, a convert to the Catholic faith and widow whose husband had died in exile after being caught attending Mass. She had managed a variety of safe-houses for priests and lay faithful. Filcock had also been Line's confessor.
On Candlemas Day, 1601, Father Francis Page was about to celebrate Mass in her lodgings when priest-catchers broke in. The priest escaped in the confusion but his hostess was arrested and put on trial at the Old Bailey on 26 February, either 1601 or 1602, indicted for harbouring a priest. Although this could not be proved, she was condemned and led to the gallows the next day. She was executed at the same occasion as Dom Mark Barkworth, a Benedictine monk, and Filcock, who had gone on trial on 23 February. This was the first execution of Catholics at Tyburn since 1595.
In St John's church there is a memorial window to Blessed Roger Filcock in the Lady Chapel, where a red candle burns to remind us of his faith and sacrifice, and our own call to holiness.