A filter for a self-propelled robotic pool cleaner includes a first chamber, a second chamber and a partition wall separating the first and second chambers to define first and second filter enclosures. A non-return device is placed in correspondence with the partition wall. The filter and non-return device are configured to receive a first flow of water and debris from the swimming pool into the first chamber so the debris is retained in the first chamber and filtered water is discharged into the swimming pool during a first cleaner operation mode, and receive a second flow of water from the swimming pool to displace the debris in the first chamber to the second chamber during a second cleaner operation mode. The non-return device is arranged such that the displaced debris cannot return from the second enclosure to the first enclosure when the cleaner is operating in the first operation mode.