The device was next to the rear set of double doors in the front carriage of the train. Twenty-six people, plus the bomber, were killed. More than 340 were injured.

On board the train was BBC News reporter Jacqui Head, who described the immediate aftermath: "There was immediately smoke everywhere and it was very hot and everybody panicked. People started screaming and crying."

After emergency services arrived and survivors were led to safety, recovery teams and investigators began work.

The Piccadilly line is 21.3 metres (70 feet) below ground at this point. Intense heat of up to 60C, dust, fumes, vermin, asbestos and initial concerns the tunnel might collapse delayed the extraction of bodies and the forensic operation.

The bomber was later named as Germaine Lindsay, aged 19.