This https://puri.sm/posts/tpm-by-default-and-free-international-... says they are moving to including the TPM in all systems, but there are some UK models left in stock without it.

The TPM is a security feature--you don't have to use it. I have not used it on my laptop but I see from the documentation that it is different from some other trusted computing systems in that the end user controls the keys and what is loadable, not the vendor.