Press release

Thames Barrier Annual Closure Sunday 27 September

Once a year the Thames Barrier is operated over a full tidal cycle for test purposes.

This news article was withdrawn on

This closure is no longer in force.

Thames Barrier with the gates closed.

The Thames Barrier is built across a 520 metre stretch of river and is an impressive example and celebration of British design.

The Thames Barrier has 10 gates including 4 large rising sector gates each spanning 61 metres and weighing 3,700 tonnes. The Thames Barrier is quite the spectacle and makes an interesting and unique day out. The closure offers visitors insight into how London remains operational as a modern city.

Order of events:

  • 6.30am: The Thames Barrier begins to close and the gates rise into position.

  • 8.30am: Cafe and Information Centre opens

  • 10.00am: Meet some of the Thames Barrier Teams with displays explaining what they do. There will be a children’s arts & crafts table, games, a souvenir gift stall and a BBQ.

  • 1.45pm: Underspill (approximate timing)

  • 4:30pm: Thames Barrier gates lowered

  • 4.30pm: Last entrance to Cafe and Information Centre

  • 5.00pm: Information Centre Closes

Please note there is no access on the Thames Barrier structure. The above times are subject to change due to the tides.

When the gates have been raised 90 degrees, the Thames Barrier is fully closed in the defence position stopping the tide going into London. As the tide continues to come in, a higher level of water will build up downstream of the barrier creating a differential in water level on either side of the gates. Shortly after high water or high tide, the gates will be further rotated by 28 degrees (or roughly 2 metres) into what is called the ‘underspill’ position.

Underspill allows the higher downstream water level of the river to rush through underneath the gates to shorten the amount of time it takes for the upstream and downstream water levels to equal. It also creates a white rush effect of water behind each of the gates, attracting many birds which come to feed on the small fish interested in the white rush water and the food it provides. The underspill continues for approximately 2 hours.


All media enquiries: 0800 917 9248, or out of hours on 0800 141 2743

Published 22 September 2015