Long bug with waving antennae

Long bug with waving antennae

Observation - Long bug with waving antennae - UK and Ireland. Description: Can run fast, flies in an upward kind of way and I think was scavenging this old bug case. 1-2cm. It waves its antennae quite rapidly. Any ID knowledge would be appreciated. Thank you!

Can run fast, flies in an upward kind of way and I think was scavenging this old bug case. 1-2cm. It waves its antennae quite rapidly. Any ID knowledge would be appreciated. Thank you!
Update: OK, I'm homing in on two possibilities. Any thoughts on my IDs would be great. :-)