Improvements in or relating to locks and lockers

A user 1 is provided with a key 10 and seeks allocation of one of a plurality of lockers 2, each locker 2 being fitted with an electronic lock 3. A terminal 4 is operable to identify unallocated lockers 2 and allocate one such locker 2 to the user 1. The allocated locker 2 has a lock 3 with a unique lock identification code and an associated sequence number. The terminal 4 is operable to write the lock identity code to the key 10, increment the sequence number and write the incremented sequence number to the key 10. Subsequently, the user 1 can present the key 10 to the lock 3 of the allocated locker 2. The lock 3 is operable to read the lock identity code and the sequence number. If the lock identity code matches a stored lock identity code and the sequence number is equal to or greater than a stored sequence number, the lock 3 will open allowing the user to access the locker. Additionally, the latest accepted sequence number is stored by the lock 3. A master key with a master key and a master sequence number may be provided.