I think Trussell Trust is a good call. She has potential to cause a lot of harm with this, not only for people that will try to copy her, not realising that you cannot provide a balanced diet on this budget, but also by her setting an example that this is OK.
It's not OK for people to have to do a weekly shop for 3 on 20 quid, it should not be accepted, and should not be shown off with gleeful pride as a perfectly manageable thing to do.
What is her relationship with the Trussell Trust now, does anyone know?