WRU official James Jones, Chairman of the West Society of Referees, answers a question about the tackle area
When a player dives on the ball do the opposing player have to let the player get up or can he jackle straight away?
There is no obligation in law to allow the player who 'dives on the ball' to get to their feet. However the 'jackler' or arriving player cannot tackle / prevent that player from getting to their feet. What the arriving player can do is stay on their feet and attempt to gain posession of the ball immediately they arrive, irrespective whether the player with the ball is on their feet or not.