When a lease ends, whether by expiry or because of forfeiture or insolvency, the tenant should remove all it’s belongings but often this does not happen.
As a landlord you will need to establish that your former tenant has abandoned the items before you can dispose of them.
First of all take photographs and prepare an inventory which, depending on value, might best be prepared by an independent professional.
Then check the lease which may contain an agreement setting out your rights in such a situation.
If not, you will need to serve a notice on the tenant under Schedule 1 of the Torts (Interference with Goods) Act 1977, requiring them (or the true owner) to come and collect them. There is no specified form of notice but it must list the items, tell the tenant where the items are stored and when they are to be sold giving a reasonable time in which to collect them. If the whereabouts of the tenant are not known the notice can be displayed on the property.
In the meantime you must look after the items and keep them safe from damage or loss. This might include insuring them if they are valuable.
If the tenant still does not reclaim the items they can be sold for the best price. The sale proceeds, less any expenses, do still belong to the tenant and if you are unable to pass these on of the tenant it would be wise to keep the funds to one side at least for a while in case of a claim from the tenant.
If the tenant does come to collect the items do make sure that the authority of the person collecting has been verified and a receipt obtained.