Encyclopaedia Britannica, 11th Edition, "Armour Plates" to "Arundel, Earls of"

2. The officers who may arrest without warrant are,--justices of the

peace, for felony or breach of the peace committed in their presence; the sheriff and the coroner in their county, for felony; constables, for treason, felony or breach of the peace committed in their view,--and within the metropolitan police district they have even larger powers (Metropolitan Police Acts 1829-1895).