I think if you are living in England and the ex-husband is living in Switzerland it might be possible. I would talk to the UK authorities (I think the CSA if it still exists) and they can help.
The UK government has agreements with a number of countries for the claiming of child benefit (alimony) from ex-husbands and Switzerland is one of the countries that is part of the agreement, so is Italy. It will be long, and difficult but might be possible. I think you need a court order because one of you doesn't live in the UK.
Start by looking at
http://www.csa.gov.uk/
Good Luck.