Lisbon, Portugal to Singapore via Manchester, UK is stretching credibility even if you do mean TAP Air Portugal.
It's also surely a major detour to go to New York that way as well.
If the price is right, they may do it, But I admit LIS-MAN-SIN would be pushing it, not because of the route but the fact its always full and fares rarely discounted to a level it would make a LIS-MAN-SIN route work.