Wilson v State of New South Wales  NSWCA 333. Hodgson JA.
60 As regards (1), if the arrest is to be lawful, this should normally include informing the person that he or she is arrested and informing the person of the reason for the arrest: Christie v Leachinsky  AC 573 at 587 – 593. However, this is not necessary if the circumstances make these things obvious, or if the person arrested prevents it: Christie at 587 – 593, R v Hoar  NSWR 1167, Woodley v Boyd  NSWCA 35 at .
61 As regards (2), a touching on the shoulder can be a sufficient act of arrest, and even this is not necessary if the arrested person submits: Alderson v Booth  2 QB 216 at 220, Hatzinikolaou,Woodley at .
64 In my opinion, if following a sufficient communication of intention to arrest and of the reason for arrest, the person in question flees, the person attempting to make the arrest can pursue that person and can complete the arrest if after a time the person attempting to make the arrest catches up with the other person, even if the time of that completion could not be considered to be immediately after the offence: Hanway v Boultbee (1830) 1 Mood & R 15; 174 ER 6, R v Howarth (1828) 1 Mood CC 207; 168 ER 1243, Griffith v Taylor (1876) 2 CPD 194, R v Jones (EJM)  1 WLR 211; and see also Sakhuja v Allen  AC 152, Shackleton v Chief Constable of Lancashire Constabulary  EWCA Civ 1975.