We have a person who was injured on 1st August but didn't report it until he started sick leave on 12th August.  He has a rib injury (unspecified) and said he tried to manage the pain with pain killers to carry on working until he couldn't manage any more.  He then didn't return to work until 26th August.  There was a delay of 11 days before he went off sick then was off for 13 consecutive days.

The legislation appears to assume that consecutive days start on the day following the injury, and that reporting for LTIs should be within 15 days of the day of the injury.  This doesn't fit our situation.

Any advice?

reeporting is to be "as soon as practicable and in any event within 15 days of the accident"

Just because you are beyond 15 days does not mean the incident is not reportable - just needs to be completed as soon as practicable

What was the incident that lead up to the pain in the ribs? Pain or an injury in itself is not RIDDOR reportable- from the HSE website:

Injuries themselves, eg ‘feeling a sharp twinge’, are not accidents. There must be an identifiable external event that causes the injury, eg a falling object striking someone. Cumulative exposures to hazards, which eventually cause injury (eg repetitive lifting), are not classed as ‘accidents’ under RIDDOR

Thanks for the input guys.  You've helped to confirm what I was thinking.

The injury was witnessed by their line manager (don't go there).  The IP was removing a ball valve from a sump via an access hatch.  He was on his feet outside the space, leaning in through an access hatch and twisting to the side.  When applying pressure on the wrench he pulled a muscle.  Just found out it was diagnosed as an intercostal strain.