The 1987 King's Cross fire that killed 31 people is one of the deadliest accidents to occur on the Underground and resulted in widespread safety improvements and changes throughout the network.

The station was extensively rebuilt in the early 21st century to cater for Eurostar services that moved from Waterloo to St Pancras, reopening in 2007.

[12] During this time, major rebuilding work took place, including a direct connection to St Pancras and a circular ticket hall.

[17] New sub-surface platforms had been under construction as part of the station improvements begun in the 1930s and these were opened in an unfinished condition on 14 March 1941 250 m (270 yd) to the west.

[23] The underground network had been at risk of fire since opening, and the limited amount of space and means of escape increased the possibility of fatalities.

By this time, the ticket hall had filled with smoke, trains passed through the station without stopping, and passengers were being evacuated.

[25] As a result, fire safety procedures on the Underground were tightened, staff training was improved and wooden steps on escalators were replaced with metal ones.

[24][27] In the aftermath of the fire, the Fennell Report recommended that London Underground should investigate "passenger flow and congestion in stations and take remedial action".

[28] In August 2000, work began to upgrade and expand the station in conjunction with the Channel Tunnel Rail Link project, in which St Pancras would be the new terminal for Eurostar services to continental Europe.

New passageways and escalators were provided to increase capacity, and ten new lifts were installed to make the station step-free.

[19] On 26 May 2006, the first section of the project was completed, with the opening of the Western Ticket Hall underneath the forecourt of St Pancras station, providing access via the undercroft.

[34] Following completion of the station upgrade in 2010, King's Cross St Pancras has eleven entrances and four ticket halls.

[42] The stainless steel sculptures, Full Circle by artist Knut Henrik Henriksen, are located at the end of two new concourses on the Northern and Piccadilly lines.

[53] York Road station closed in September 1932 and was around 600 m (660 yd) north of King's Cross St Pancras.

[3] There is a siding north of the Victoria line platforms to enable trains from Brixton to terminate, turn around and head back south.

James Cunningham was arrested later that month and sentenced to life imprisonment with hard labour for causing the attack.

[58] On 28 May 1959, the leading car on a Northern line train derailed just after leaving King's Cross St Pancras, heading for Euston.

[60][61] The death toll was the highest of all the incidents, as the Piccadilly line is in a deep tube south of King's Cross and there was nowhere for the blast to escape.