Only the costs of purchasing uniform for directors or staff can be claimed.
Clothing for personal use cannot be claimed, and general business attire cannot be claimed as a uniform expense. This is because you cannot claim for ordinary clothing which would form part of an everyday wardrobe, even if you would not be likely to wear the clothes anywhere other than at work.
Protective clothing that you have to wear for your work is very much allowable, as it is a business necessity.
Clothing can also be claimed, in the words of HMRC, if it's “a recognisable uniform that shows you’ve got a certain sort of job - like a nurse’s or police uniform”.
Another situation in which clothing qualifies is if you are an actor or entertainer and the clothing is a costume.
Record in Crunch as Employee Costs > Staff Welfare