How can I get out of the lease now that I no longer want these business premises?

The first step is to check what rights the lease gives you. For example, you may have the right to assign the lease to other (so that they take over the tenancy), sublet the premises, or give notice to bring the lease to an end.

Alternatively, you can attempt to negotiate the surrender of the lease with the landlord. The landlord might expect payment for agreeing to this.