The Construction Industry Scheme (CIS) is a set of special rules for handling payments for construction work that contractors make to subcontractors. The scheme covers all 'construction operations' - construction work - carried out in the UK, as well as some other related work.
If your business is involved with construction operations then it might operate as a contractor or as a subcontractor - or as both. The terms construction operations, contractor and subcontractor have special meanings under CIS and they're defined in the rules of the scheme. We can either help you understand this scheme or take over the administration of the scheme on your behalf.