The Chairman has discretion to allow this. The model standing orders 3e and 3f state:-
e) Members of the public may make representations, answer questions and give evidence at a meeting which they are entitled to attend in respect of the business on the agenda.
f) The period of time designated for public participation at a meeting in accordance with standing order 3(e) shall not exceed ten minutes unless directed by the chairman of the meeting.
There is no prescribed format for this process. It's usually taken as an agenda item at the start of the meeting, but need not be. We have District and County Councillors at every meeting and after their reports, members of the public may ask them questions. As long as the Chairman is clear about when the public can and cannot speak, it all goes without a hitch.