Hook landslip: What caused it and how long will it take to fix?

• WATCH: Drone footage of the damage the landslide caused to the track

Words by ITV News Meridian Journalist Grace Williams

Work is continuing to fix a huge landslip which damaged the main rail line which runs from Hampshire into London.

A section of the embankment in Hook collapsed on Sunday 15 January, leaving one of the tracks hanging in mid-air.

The landslip has caused major disruption for commuters travelling in and out of London, with people asked to avoid travelling if possible.

So how did the landslip happen and what does this mean for passengers?

What happened?

A 44-metre landslip took place on the line from London to Basingstoke, on the embankment to the north east of Hook station in Hampshire on Sunday 15th January.

A section of the embankment on the line from London to Basingstoke collapsed on Sunday 15th January, north east of Hook station in Hampshire.

The 44-metre landslip has left one of the tracks hanging in mid-air.

The damage has left only two of the four-track railway passable, with both these tracks designed for London-bound trains only.

What is a landslip?

A landslip (also known as a landslide) on the railway is generally defined as when soil, rocks and earth fall onto and either wholly or partially block the track.

The slopes on either side of the track will need to be strengthened, as following a landslip, the earth is then permanently weakened.

Network Rail said it's important to stabilise the area and improve drainage otherwise it would be "much more likely that there will be further landslips."

What caused it?

Network Rail said that the embankment was made of a mixture of London clay and other local soils which had become saturated after days of heavy rain.

The soil then gave way along a 44-metre section and slid out from underneath the tracks.

How long until it's fixed?

Network Rail hasn't been able to confirm how long the repairs will take, but said it's working with its suppliers and should have an idea of timescales soon.

Network Rail Wessex route director Mark Killick said: "Over the last couple of days, we've seen some intensive rainfall and yesterday afternoon, we started to see some movement with our railway embankment.

"Overnight that movement has continued and now the track which sits on top of the embankment is not supported, so for safety reasons, we've had to close the railway.

"We've got engineers on site carrying out assessments to work out what needs to be done to safely rebuild the embankment to reopen the railway but it is going to be a huge task."

What does this mean for passengers?

South Western Railway says services between Basingstoke and London Waterloo are extremely limited and people are being asked to avoid travelling if possible.

Passengers are also being told to expect disruption in the coming days due to closures and to check before travelling, as there will be significant changes to the train services.

Network Rail said a train plan to provide journey options for customers on the route is due to be published soon.