The total distance between the two locations is 82 miles. It will take about 1 hour and 45 minutes.
London St Pancras International Station.
Paddington
St.Pancras
London Paddington.
Assuming you meant public transport: You can get a Thameslink train from Gatwick Airport Train Station to St. Pancras station. Then a short walk to Euston station where you can catch a Virgin Trains service to Stafford (the main station in Staffordshire).
the London train station
The busiest train station in the UK is London Waterloo.
Take a train from London Waterloo station.
train from guildford station to London Waterloo
London Paddington. Catch a train heading for Bristol Temple Meads.
Kings Cross Station
I believe it is Liverpool Street Station in London.