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with a merino base layer, then probably. But it really depends on a lot of factors; do you run hot or cold? How hard do you ride? Do you ride in dog shit weather? Where do you ride?
I run a little hot and generally ride at a reasonable pace. I wore a LS wind block brevet jersey with a merino mesh LS baselayer for the majority of winter on my commutes (35k each way) through the countryside (except when it rained) and it was great for me. However, a colleague of mine would have frozen (but then they're smaller and run a lot colder).
Would the jacket with a normal jersey and arm warmers be enough for British winter?
n.b. instead of a winter jersey