The tenant of this thread is is so weak.
Many thousands of UK travels already make the choice NOT to connect over LHR every day, flying from regional airports via AMS/FRA/CDG and even further affield from Man/BHX/NCL/GLA via Dubai going East or with the exception of NCL (Insert EDI instead) going west via EWK.
These are at the expense of BA/VS and the UK economy however they are convenient and in the main competitive.
In the case of Manchester there is an extensive network of routes connecting the city globally WITHOUT transiting ANY London airport. Even Oneworld frequent flyers can avoid London to get to Asia (Finnair), South America and Miami (IBERIA) and the whole of the USA (American daily to JFK and Chicago)
Did you know you can buy a BA codeshare for Manchester to Milan/Dusseldorf/Hanover direct to this day (On FLYBE !) .
Add Qatar / Etihad /Turkish/Singapore/US Airways/Delta Virgin Atlantic - You get the picture. Transfer over LHR is an option NOT an obligation.