Liverpool-London route. Been attempted by many and all given up. Since 87-Present
Manx
British Midland
VLM
EasyJet
Euroceltic?
On paper it looks like a possible route, but MAN has stronger links with BA and bmi. bmi found the MAN-LHR slow to take off, as BA had long established customer base.
And to be honest if BM could not get Liverpool-Heathrow to work, then to Luton has no chance.