Government officials feared Birmingham was in danger of having an H Bomb dropped on it during the 1950s, documents released today reveal.

Hundreds of times more powerful than the atomic bombs dropped on Hiroshima and Nagasaki at the end of the Second World War, the hydrogen bombs would have completely wiped out the city, killing hundreds of thousands of people.

But the documents show that civil servants were worried not just about the destruction of Birmingham and other major urban areas, but also the great British cuppa.

The previously top secret report describes how the tea situation would be "very serious" if there was a widespread attack on the UK by both A bombs and H bombs.

Rationing of Britain's favourite brew was one of the contingency plans being considered by the Government as part of measures to ensure the nation's food supply did not dry up in the event of nuclear war.

One official noted: "The tea position would be very serious with both a loss of 75 per cent of stocks and substantial delays in imports and with no system of rationing it would be wrong to consider that even 1oz per head per week could be ensured.

"No satisfactory solution has yet been found."

The 1950s saw a nuclear attack from the Soviet Union emerge as the biggest threat to the West in the aftermath of the Second World War.

As the Cold War arms race intensified, the Hydrogen bomb replaced the atom bomb as the most powerful weapon of mass destruction on the planet.

Ministry of Food officials compiled a list of feared targets "for departmental planning purposes only" that put London, Birmingham, Merseyside, Manchester and Clydeside as H Bomb targets.

Those listed as A bomb targets were Tyneside, Teesside, Leeds, Sheffield, Hull, Derby, Purfleet in Essex, Southampton, Portsmouth, Bristol, Plymouth, Cardiff, Coventry and Belfast.

The document, document released under the Freedom of Information Act by the National Archives in Kew, south west London, warns: "The present assumption is that each target would receive an H or A bomb respectively."

It stressed the need to plan in order to be "completely ready to maintain supplies of food to the people of these islands, sufficient in volume to keep them in good heart and health from the onset of a thermonuclear attack on this country."

The report continues: "It has become increasingly clear that the severity of the attack which the enemy could launch would produce a catastrophe in the face of which past measures would be fatally deficient."

Birmingham had just emerged as the country's official second city at the time, replacing Glasgow as the population topped the one million mark. Immigrants from Ireland, Pakistan and the West Indies were arriving en masse, a new shopping centre had opened at the Bull Ring, Birmingham brewer Davenports was being advertised on television and its beers delivered to people's homes.

Government officials believed an H bomb strike on the city would require a relief programme on a scale far greater than that put into action during the Blitz.

Arrangements for the stockpiling of food, emergency feeding and equipment and the availability of bread, milk, meat, oils and fats and tea and sugar were listed for discussion.

The former war time emergency bread organisation, "which operated so efficiently in the last war" had already been set up again, and emergency officers from the trade had been appointed, one document noted.

Studies from the regions had shown that this organisation could "with difficulty" cope with the problems caused by a "few atom bombs" on the principal cities.

But in the event of an H bomb offensive "It would however be unable to maintain bread supplies under the conditions envisaged".