I would like to know if I need an import licence for cleaning materials from Israel.
There are controls on exports of military or paramilitary goods, technology, artworks, plants and animals, medicines and, and in your case, chemicals. Licence requirements may depend on the potential use of the item - e.g. if it has a military application (usually referred to as dual-use goods) and where you are exporting to.
There are also controls on imports including firearms, plants and animals, foods, medicines, textiles and chemicals. Whether you need a licence can also depend on where the goods are coming from.
Exporting or importing controlled goods without the right licence is a criminal offence, so it's important to check first.
A full list of import restrictions and prohibitions is listed on the HM Revenue & Customs site.
See also: Import duty explained