Lights out: Britain plunged into darkness as WWI centenary marked

A 'lights out' event took place across the country last night to mark the centenary of the day Britain entered the First World War.

People were invited to switch their lights off between 10pm and 11pm - the hour war was declared on 4 August 1914.

An installation called Spectra by Japanese artist Ryoji Ikeda

Paul Gaitley (whose two grand-uncles were killed on the same day in October 1914 Able Seaman Arthur Gaitley and Private Jack Gaitley) and Alison Schulte holding candles outside Westminster Abbey

Service men walk past the grave of the Unknown Warrior, Westminster Abbey

An oil lamp burns beside of the grave of the Unknown Warrior

Members of the congregation hold candles at Westminster Abbey

Buckingham Palace is immersed in darkness

10 Downing Street

The Houses of Parliament

National Gallery, London

Piccadilly Circus

A member of the congregation lights a candle at Bath Abbey

The face of Big Ben as the clock strikes 11

More: Each one of these 888,246 poppies represents one British military fatality in WWI