This is a legacy of the British European full service days, and was essentially offering passengers from GLA and EDI a connection at BHX. A codeshare would no longer be necessary as both GLA and EDI have services to EWR.

The GLA codeshare on the BHX flights started after GLA had its own direct flights to EWR with CO

I’d be surprised, considering CO fly to MAN (only 35 miles from LPL) and Flybe’s status as a lo-cost airline versus CO’s status as a full service carrier.

They do it on the BHX flights. you can fly GLA-BHX-EWR or fly BHX-GLA-EWR even though you can fly direct from both GLA and BHX to EWR

Will they continue with the code share with CO on the LPL-GLA route to connect with GLA-EWR