The RMT union said about 1,800 members, including train crew and some drivers, are taking action against threatened job cuts and disputes over working conditions and safety.
Virgin Trains East Coast, which operates services between London, eastern England and Scotland, said it was making changes to customer-facing roles.
The company said it would be running a full timetable during the strike but there will be some changes to on-board catering and it may not be able to open the food bar or run a trolley service in standard class, and the first class menu will be reduced.
I think the message is to stock up on food before you travel.
Welcome back to live updates for Beds, Herts and Bucks
Katy Lewis
BBC Local Live
Welcome to another week of regular live updates of news, sport, weather, travel and more.
This morning, workers on Virgin Trains East Coast have begun a 24-hour strike which could affect some journeys. We'll bring you all the information we have about that.
We'll also bring you up-to-date on some of the news you might have missed over the weekend, including the latest on budget airline Monarch's licence to sell package holidays, and how Milton Keynes athlete Greg Rutherford got on in Strictly.
We'll also see what the weather has in store with a full forecast.
Live Reporting
Alex Pope
All times stated are UK
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Latest PostWoman, 82, sexually assaulted in Bletchley
Katy Lewis
BBC Local Live
An 82-year-old woman has been the victim of a daylight sex attack in Bletchley, described by officers as "horrendous".
The woman was assaulted as she walked on a path near Buckingham Road at about 13:00 on Friday.
A man, described as white and in his early to mid-20s, with a large build, pushed her to the ground and attacked her before walking off.
He was wearing a black beanie hat, black jacket and black trousers. He was carrying a black rucksack over both shoulders.
Today's weather: Mainly dry this morning
Kate Kinsella
BBC Look East weather
It's a chilly start to the new working week and this morning will be mainly dry with sunny spells.
It's due to turn cloudy later and there could be some heavy rain, hail and thunder in the Beds, Herts and Bucks area.
Maximum temperature: 15C (59F).
Virgin Trains East Coast rail staff on strike
Katy Lewis
BBC Local Live
Workers on Virgin Trains East Coast have begun a 24-hour strike this morning in a long-running dispute over jobs.
The RMT union said about 1,800 members, including train crew and some drivers, are taking action against threatened job cuts and disputes over working conditions and safety.
Virgin Trains East Coast, which operates services between London, eastern England and Scotland, said it was making changes to customer-facing roles.
The company said it would be running a full timetable during the strike but there will be some changes to on-board catering and it may not be able to open the food bar or run a trolley service in standard class, and the first class menu will be reduced.
I think the message is to stock up on food before you travel.
Welcome back to live updates for Beds, Herts and Bucks
Katy Lewis
BBC Local Live
Welcome to another week of regular live updates of news, sport, weather, travel and more.
This morning, workers on Virgin Trains East Coast have begun a 24-hour strike which could affect some journeys. We'll bring you all the information we have about that.
We'll also bring you up-to-date on some of the news you might have missed over the weekend, including the latest on budget airline Monarch's licence to sell package holidays, and how Milton Keynes athlete Greg Rutherford got on in Strictly.
We'll also see what the weather has in store with a full forecast.
If you'd like to get in touch, you can email us, tweet us or contact us via Facebook.
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