Cutting raspberries back.

[greenishfing]

A few years ago I bought my niece a few raspberry canes (her favourite fruit) as a housewarming present. She is definitely not a gardener but despite all the odds they have thrived and they now give enough raspberries for jam.
One of my sisters (another of her aunts) was at her house yesterday as my niece is on holiday.My sister went to check up on the house and stop the raspberries going to waste!
My sister rang me and said the raspberries are just about finished, she only managed to pick a pound or so but the canes are about 6 feet tall and untidy. Her question was could she cut them back. She said they look as if nobody has ever touched them.
I have no idea but told her "NO".
I know full well that if this is the wrong thing to do I will end up getting the blame when they either die or give no fruit next year.
My question: when and how should they be cut back?

[ESBkevin]

A bit early for many raspberries to be finished although there are some varieties that are early.

I would wait a few more weeks so that the roots benefit from the leaves a while longer and then hack them to the ground. Others may know better.

[It never rains..it pours]

I presume they are summer fruiting variety, if so leave any cutting them back till autumn and only cut the dead canes (the VC method that i use too), these will only be ones that fruited heavily this year. They always look a bit of a mess now as new canes for next year are coming up amongst the others