My husband died unexpectedly last week.I am English, with

sorry - mistake

See section 11.2 and 11.3 of this UK Governmemt website.......

https://www.gov.uk/government/publications/bereavement-information-for-…

Also, onother UK Gov website says ...

Bringing ashes home

When leaving a country with human ashes you will normally need to show:

• the death certificate
• the certificate of cremation

Each country has its own rules about departing with human ashes and there may be additional requirements. Read information about the country where the person died to find out what you need to do. You’ll need to fill in a standard customs form when you arrive home.

Hope it helps

You will need the cremation certificate or a letter from the crematorium, the death certificate and a customs declaration slip.  The urn must be sealed - which it will be when the crematorium gives it to you.  You will have the paperwork from Italy allowing the export of ashes.   When I had to do it for a client, I also needed a nulla osta from the mayor, but the funeral directors will be able to help on that, Im sure.     To be on the safe side I would stop and declare it.