Not valid on trains timed to depart:

• London Euston after 04:29 until 09:05 but not valid on the 16:10 (16:10 is valid for travel on Fridays)
• Milton Keynes Central after 04:29 until 09:05;
• Watford Junction after 04:29 until 09:00;
• Reading before 08:35 and after 17:10 until 19:01;
• London Marylebone after 04:29 until 09:05;
• London Paddington before 08:10 and after 16:40 until 19:01;

Break of journey is not permitted.   

Not valid on trains timed to arrive:

• London Euston after 04:29 until 10:25;
• Milton Keynes Central after 04:29 until 10:00;
• Watford Junction after 04:29 until 10:20;
• Reading before 09:40;
• London Marylebone after 04:29 until 10:25;
• London Paddington before 10:10;

For travel on CrossCountry services use 2V.