Why This Is Hell

I am buying train tickets - it's not for me, it's for a friend, Mr Burglar - and obviously these days you buy two singles anyway, but I s/he needs to visit one place and will call in on another whilst I one is up that end of the country.

That's ninety minute journey to London.
Over two hours to York
Less than an hour from York to Hull
About three hours Hull to London
Ninety minute journey back here.

Guess which is the most expensive leg?

Am also buying tickets for my their Great North Jaunt: London-Durham-Edinburgh-Newcastle-London. So far each leg is just about doable for £7.50, although I paid a quid more to not change up to Durham on a rather pricier ticket but they will have to pay more to get up to London to guarantee a 12.30 train. 40 mins should be enough Victoria-King's Cross. But.

Edit: Newcastle-London is more expensive. Pondered whether it's worth paying a fiver for a journey which is shorter by 30 minutes. Ponder hourly rate of pay and decide it is, but after soul searching. (Last year I travelled first class because it wa actually cheaper. And I got a worse than indifferent cup of coffee. Or was it tea? Couldn't tell at the time, can't remember now.)