Globespan, Ryanair, Easyjet operate from Glasgow, Prestwick and Edinburgh to Faro Airport. You can get a taxi from Faro Airport to Faro Train or Coach Station and then a cheap bus or train to Lisbon in about 3 hours.
Train will only really be possible if you arrive prior to 15:00.
However, there are Rede Expressos, EVA and Renex buses to Lisbon with the last departure at 20:30, arriving 23:45.
