Why can't ubuntu bash see composer in windows 10?

Question

bash

This is bash

[email protected]: /mnt/c/Users/User# composer
/mnt/c/ProgramData/ComposerSetup/bin/composer: 14: /mnt/c/ProgramData/ComposerSetup/bin/composer: php: not found

And here is the Windows command line

C:\Users\User>composer
______
/ ____/___ ____ ___ ____ ____ ________ _____
/ / / __ \/ __ `__ \/ __ \/ __ \/ ___/ _ \/ ___/
/ /___/ /_/ / / / / / / /_/ / /_/ (__ ) __/ /
\____/\____/_/ /_/ /_/ .___/\____/____/\___/_/
....

Have I installed composer correctly?
I see bash swearing at what's in

C:\ProgramData\ComposerSetup\bin

no php, but should it be there?
But in the folder with the PHP used, I also have a composer file