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Two train operating companies are warning of a reduced services throughout the day on Saturday due to a shortage of train crew.

Thameslink and Great Northern, which are both owned by Govia Thameslink Railway (GTR), said their services will be cancelled or revised until the end of the day on Saturday.

They added some services will also start and terminate at different stations than usual.

Passengers are being advised to leave up to an extra 30 minutes to complete their journeys on Saturday due to anticipated disruption.

They have been warned that they might need to change trains, wait longer for a service or use another public transport option to complete journeys.

Ticket acceptance has been arranged by GTR, including on some Southern and London Underground services and also on Metrobus services between Three Bridges and Horsham/Redhill.

GTR added that its journey planners are up to date with services that are due to run.

The company warned that late night services will also be affected, so passengers should check before travelling, especially for journeys to and from Gatwick and Luton airports.

GTR said: "A combination of driver training, sickness, and annual leave, can sometimes take Great Northern and Thameslink to a position where they find it challenging to cover the service."

The BBC has approached GTR for a further response.

Engineering works

Additionally, due to engineering work on the Thameslink network on Saturday, "various lines" will be closed.

On Saturday, Thameslink said a reduced service would be operating through London Bridge and also between London Blackfriars and Three Bridges.

Trains between Luton and Rainham would run to an amended timetable.

Meanwhile on Saturday and Sunday, Thameslink trains will not run to, or from, Sutton via Mitcham Junction.