Good question
Law 8.3 is the answer
If Red had not been illegally tackled would he have been able to pick up the ball and score under the posts ?
It's complicated :
- if you apply the 'beam him up' principle and remove blue 14 completely, the answer is this case is yes , so should be a PT
- but the 'beam him up' principle seems to have been deprecated, now refs seem to imagine what would have happened if Blue had stayed legal --- which is that the try would have been scored ... in the corner. So no PT.
If you are going to award a PT - Its best if you blow immediately, before red score anyway, although some times it might happen so quickly you don't get time. In this case think quick blow slow , take a second , don't award the try but instead award the PT.