Loughborough to London

Loughborough to London is best done by train: you will be able to get a much cheaper fare if you book in advance at http://www.eastmidlandstrains.co.uk/EMTrains. The trains arrive at St Pancras station and the Victoria Line on the Underground runs directly from Kings Cross Saint Pancras station to Victoria. If the Victoria Line is not working, take the Piccadilly Line to South Kensington and the District Line to Victoria.

The 9am flight from Gatwick may be more difficult depending on your check-in time. The earliest express train from London Victoria is at 3:30 am and gets to Gatwick about 4am. There are then trains at 4:30, 5:00 and every fifteen minutes after that. The Underground does not start until about 5am so you may well have to get a pre-booked taxi to Victoria. If you do have to do that it might even be worth getting a taxi all the way from the hotel to the airport: if you are travelling before 7am the traffic shouldn't be as bad as it would be later.

While you can use a US credit card to buy tickets at any UK train station, not all train companies accept US cards for online booking. If the East Midlands site given by Philip doesn't accept your card, book Loughborough-London at www.eastcoast.co.uk. Even though you won't be traveling on an East Coast train, you can book any UK train on that site and it will accept your card and you can get advance purchase discount fares.

If your airline recommends that you be at Gatwick three hours before your flight home, you can take the Gatwick Express from Victoria to Gatwick, leaving at 05:30 and arriving at 06:00.

As Philip said, you can take a taxi from Notting Hill to Victoria. Or you can take bus N52 from Notting Hill Gate to Victoria, departing at 04:55 and arriving at 05:18.