Possibly a larva type creature

Possibly a larva type creature

Observation - Possibly a larva type creature - UK and Ireland. Description: This was seen on stone steps on Portland along the coastal path. It moved by scrunching the rear end up and then moving the whole body forward. It was not, however, a caterpillar. Any ideas please

This was seen on stone steps on Portland along the coastal path. It moved by scrunching the rear end up and then moving the whole body forward. It was not, however, a caterpillar. Any ideas please