EastMids post was one of the most ill informed I've read on this topic for a very long time. He seems to have woken up in the late 1970s. I have only just caught up on this thread and he already has had a comprehensive reply.
I would add that he may not realise that Manchester is now the third most visited destination in the UK by overseas business, leisure and VFR travellers combined. Those figures are based on bed nights and passenger surveys at stations, the airport and certain visitor attractions. The visitors don't all come through London, or even visit there. Add in the overseas visitors to destinations within the catchment area where no visit to the city or the conurbation is made and the larger region has shown an average sustained visitor growth over the last 16 years, with the 2008 recession causing the only dip, the effects of that recession being totally ignored by East Mids when he mentioned the airport passenger figures.