Why would my Hoover AS110 not spin up to full spin speed?

My Hoover AS110 does not spin up to full speed but goes through all the cycles, wash rinse etc.

The program goes through exactly as it should, except when it seems about to spin up to full speed, after the initial, slower 'distribution' phase it gains some speed then slows down and continues the cycle.

I'd appreciate any information or help.

Tim