Holding Deposit

[kanwal3017]

The letting agent has told me that he has received a holding deposit from a prospective tenant. Does this mean the the tenant now cannot back out

[Buenchico]

It's not straightforward. While the purpose of taking such a deposit is to tie the prospective tenant to taking on the tenancy, it might not actually be enforceable in a court of law. See here for an explanation:
https://www.landlordzone.co.uk/information/holding-or-pre-contract-deposits/