Lookee that hat!

Several years ago, during our residency in Birzeit, Palestine, our landlord needed to do a little repair work on one of the buildings. Naturally, the spade turned up an item of interest (one cannot disturb earth in Palestine without hitting something!). It was an old steel helmet that had been filled with plaster. Maybe it was a bucket in its second life? It looked like a WWI Tommy helmet to me. Any other guesses?