An offer letter is usually sent before the formal employment contract. Once accepted, it creates a binding contract. The offer should be conditional (subject to references, right to work check, DBS if applicable) until all conditions are satisfied.

• An accepted offer letter is legally binding — be careful what you offer
• Right to work check: mandatory before employment starts — face a civil penalty if you don't
• Reference conditions: always make offer conditional on satisfactory references
• Offer letters and employment contracts: the full contract should follow promptly
• Withdrawn offers: a validly accepted offer cannot be withdrawn without potential liability

Legal reference: Employment Rights Act 1996; Immigration, Asylum and Nationality Act 2006 (right to work); Equality Act 2010