See para 36:https://www.bailii.org/uk/cases/UKUT/TCC/2020/212.html
Not that it helped this particular bloke much (who unusually wanted to be criminally prosecuted to dodge a £12m VAT penalty).
Interesting also as confirming that pretty much no civil tax penalty cases will be subject to criminal standard of proof.
[Edit] Although note para 33 here that where fraud is alleged cogent evidence is usually needed nonetheless: