If you have Employers Liability insurance, and have recently taken this up, or renewed, you may find your insurance provider writing to you about something called ELTO. This is a fact finding mission for the Employers Liability Tracing Office, and you will be asked to provide your employer reference for their records.
ELTO is a recently formed organisation, replacing the litle known predecessor ELCOP (Employers’ Liability Code of Practice) and it looks set to be a far more effective system than ELCOP. Currently Insurance Provider membership of ELTO is voluntary, but if successful it could possibly become mandatory in the future. Employer Liability insurance providers who do become members are subject to a mandatory requirement to provide details of all insured entities, so if your insurer is a member, they will write to you requesting your payroll reference. If you are satisfied that this request is genuinely from your insurer, then you will need to provide them with your HMRC employer reference, which can be found on any recent HMRC paye correspondence, or P60.
A factsheet about ELTO can be found at: