Cobra is the dramatic name for the civil contingencies committee which leads responses to national crises.
Tony Blair and Charles Clarke have chaired Cobra meetings
The group is named after the Cabinet Office Briefing Room A in the bowels of Downing Street where it normally meets.
It has been convened in recent years for the 7 July London bombings, the fuel protests and 11 September attack.
Its members vary according to the issue being dealt with, and can often include Tony Blair, senior ministers and police and intelligence chiefs.
The committee is meeting now to discuss the UK's first case of bird flu in the wild - after a dead swan was found to have the disease near Cellardyke in Fife, Scotland.
The only minister at Thursday's first meeting is environment minister Ben Bradshaw.
There are also representatives from the Department of the Environment, Food and Rural Affairs (Defra), the Scottish Executive, the Department of Health, the Cabinet Office and 10 Downing Street will.
The seniority of Cobra's members is intended to ensure it gets things done quickly, and ensure that what needs to be done is done.
Cobra meetings are frequently chaired by the prime minister and home secretary, which happened after the London bombings on 7 July in which 56 people died.
Then, the committee covered the investigation and looked at what steps could be taken to avoid further attacks.
A hastily arranged meeting of Cobra was also called following the incidents on the 21 July.
Cobra does not necessarily meet in Number 10 - there are a number of secure meeting places in the Whitehall area.
An emergency meeting of the committee was called on 11 September 2001 as soon as the enormity of the attacks on the World Trade Center and Pentagon became clear.
It was also convened after two suicide car bombings in Istanbul hit the British Consulate General and the HQ of HSBC bank in the city in November 2003, killing 61 people including British Consul-General Roger Short.
The committee considers issues such as whether to invoke the powers contained in part two of the Civil Contingencies Act, which gives considerable extra powers in times of a serious emergency.
They were designed to cope with a far larger incidents than that which struck London on 7 July, particularly one involving chemical or radiological material, such as a nuclear "dirty bomb".
They would allow a minister to suspend sittings of Parliament if necessary and to declare a bank holiday to shut down businesses.
By executive decree, property could be destroyed or requisitioned, assemblies banned, freedom of movement limited, the Armed Forces mobilised and special courts set up to deal with suspects if it was felt another atrocity was planned.