The initiative is being coordinated by Mutual Aid Alnwick and follows in the footsteps of a similar scheme in Seahouses.
Katie Roskams, founder of Mutual Aid Alnwick, said: “We're all struggling now more than ever and so many people are showing solidarity under these very difficult circumstances by helping others in their community.
“The idea's very simple - leave food, household items, books or DVDs if you're able, and take anything you want if you're in need.
“We're grateful to have permission from BT to use the phonebox for the duration of the lockdown, and we're very thankful to those who've donated items to make this possible.”
The community larder is located near the Dorothy Perkins store on Bondgate Within.
Katie is making regular checks and also giving the surfaces a wipe.
Long-life milk, tinned foods and books are among the items to have been donated.
“So far, so good - people seem to be adding things and taking things, which is just what we had planned,” she said.
“We could do with packets of antibacterial wipes. We had two on Sunday and they're both gone now. If people could avoid taking them and the hand sanitiser, that'd be helpful too.”
She also thanked Communityat NE66 and Rachel Douglas, who initiated the Seahouses scheme, for their help.
The project is designed to complement the work of Alnwick District Food Bank.
The phone is still in working order.