Train from London to Northampton

Go on this site :>https://www.traintickets.com/?/
Put London Euston to Northampton and select times. Check it for today* and also see if fares are cheaper by booking Advance tickets ahead for specific trains. Also note the different prices and the fact that split tickets can be cheaper in some cases.
* Things are not accurate today due to the heat causing problems/ cancellations.

I see that by travelling off peak it can be done for £28.46 return (and not tied to any specific off peak train) by splitting the ticket at Milton Keynes - even though you stay on the same London North Western Railway train throughout. (The split saves £7.79 on the through ticket price) - something which the London North western Railway site does not tell you. These are pay on the day fares without a Railcard.

Also check out the fares on this site:>https://new.trainsplit.com

You can book direct with the train company if you wish or buy tickets at station.

There is only one company that operates trains from London to Northampton. London North Western. From Euston
You should be able to find an Advance Single at £10.00 You have to travel on booked train with these tickets
Use their website, or any other train operating company. Do not use other third party sites
Suggest you consult www.seat61.com for information on rail travel in UK including how to book tickets from abroad

Thank you so much for the info!!!