TV and stage actress Juliet Stevenson says it was "uplifting" speaking to members of the public donating to today's telethon.
She said helping take donations had made her aware of just how much British people care about what's going on.
She spoke to ITV News Correspondent Rageh Omaar at the event:
More top news
Andreea Cristea, 29, remains in a critical condition after being rescued from the Thames after a terror attack along Westminster Bridge.
The Prime Minister has praised the former soldier's "huge professionalism" in trying to save the life of Pc Keith Palmer.
The man who carried out the Westminster attack is thought to be British born and was once investigated by MI5, the Prime Minister has said.