Domdaniel: 22.Kb1! is a beautiful winning move. After this, Nunn's attack is brown bread.
Instead, 22.bxc3 only draws: 22...Qxa3+ 23.Kd2 Qxc3+ etc.
Or 22.fxg7 Rxa3 23.bxa3 Qxa3+ and a perpetual.
22.Kb1 stops the drawing lines and one of Black's pieces will be left hanging.
Nunn had lost an earlier game to Hebden in this opening, and complained about the misery of losing to variations with silly names.
The Barry Attack is not named after anyone called Barry (though a 19th century Bostonian, John Barry, and the English editor/player Baruch Wood were suspected at various times). It is simply rhyming slang for 'rubbish', from 'Barry White' = 'shyte'. 'Brown bread', if you haven't guessed, is rhyming slang for 'dead'.
What a load of Barry.