Yuen's call-out turned out to be an artillery shell fired by the British in their unsuccessful attempt to repel Japanese forces in 1941. The other vintage ordnance, defused by Brittain on October 8, was dredged up in the East Lamma Channel along with other fill intended for the Penny Bay reclamation for future development of Disneyland.

Last year the police unit's Brothers-in-Bombs rendered safe 139 explosive items, half of which were from World War II. 'Quite literally thousands have been dealt with', since the Explosive Ordnance Disposal Bureau's (EOD) inception in 1971, says Brittain. The city does have the hapless distinction of having been targeted at times during World War II by both Allied and Axis forces.

Buried bombs represent a flashpoint where Hong Kong's future could collide with its past. With the population estimated to surge to nine million by 2029, and with its attendant property development, construction, roads and reclamation will continue to expose munitions. 'Publications have generally overlooked Hong Kong's airwar history,' says Ian Quinn, an airline pilot who has spent nearly seven years researching World War II bombing missions over Hong Kong. The Americans dropped about 4,000 bombs, says Quinn, 51, who says he has scoured some 150 declassified US mission reports. Brittain says about 30 per cent of all bombs dropped fail to explode. 'Sooner or later they have to be accounted for,' Brittain says.

Hong Kong was first hammered in December, 1941, by the Japanese for nearly a month before surrendering on Christmas Day. Allied forces in turn pounded the Japanese for four years. The raids were sporadic until 1943 when the Americans 'sped up' by dropping sea mines along with the Australians, Quinn says. Come February 1945, the Americans had retaken the Philippines and, no longer dealing with the logistical impediment of staging raids from far-flung parts of China, 'stepped up attacks to almost daily and nightly harassment' for eight months until the Japanese surrendered in September 1945, Quinn says.

One of the biggest American raids occurred on October 16, 1944. Eight low-level B-25s attacked ships in Victoria Harbour while 28 B-24s bombed the Kowloon docks. They were escorted by a total of 58 P-40 and P-51 fighters.

Further compounding the potential of a 455kg shell to level a 100-metre radius - the reason for compulsory mass evacuations like that of 4,000 people in Yau Ma Tei in February - is that many bombs were booby-trapped.

During World War II the US, for example, dropped 227kg shells with delayed fuses of minutes up to days - in the tail. To prevent ground forces from disarming the bomb before it went off, a second mechanical fuse was secretly hidden in the tail which, in cases of the first one being improperly defused, acted as a second trigger mechanism.

Somewhat fortunately - we are still talking about TNT - the most common ordnance the EOD encounters are 60cm shells weighing 45kgs. Such shells are often found in sites targeted by the sorties, including Kowloon and Taikoo docks, Aberdeen and the British army's headquarters in Admiralty near an area which now happens to be earmarked for the construction of a new government office building.

A Government Works Bureau spokes-man says staff are reminded regularly to pay particular attention to such objects found on sites but dredging work, by nature, is performed blindly. Which is probably why Hong Kong's greatest catastrophe resulted when a dredger sucked up what was estimated to be a 227kg bomb in 1993.

'The near 10,000-tonne dredger was written off by the explosion,' says Brittain. Had the blast not been mitigated, as the dredger's head was 20 metres below the seabed at the time, the ship carrying the dredger 'would have immediately sunk with massive loss of life', he says. Subsequently, only one worker was injured in the incident off Tsing Yi island.

The chances of munitions spontaneously exploding, unprodded, upon being discovered, is 'extremely improbable', says Brittain. The general public has little to worry about regarding their safety, provided they act with common sense, he says. All rather obvious yes, but Yau Ma Tei residents, when a 225kg bomb capable of flattening 200-square metres was found there in February, were reported to have been 'kicking, hammering', indeed 'playing' with it, only 'in their spare time' of course, according to a restaurant owner - for two days. Apparently, residents mistook the weapon of destruction for a gas cylinder.

It was the kind of job that, when EOD disarmed it after 10 tense hours, would have earned the unit's members the George Medal, which is bestowed by Britain's queen to civilians and soldiers for high acts of bravery. 'We call that a George Medal type job,' says Brittain, disarmingly.

The wares of war

The most common munitions found are Japanese and British artillery gun shells, hundreds of which have been found to date. The ballistic steel shells are usually either a 9.2-inch calibre , a metre in length, and weighing 172kgs or a six-inch calibre shell, 60cm long, weighing 45kgs. The shell found in Tsuen Wan Park was three-inch diameter, 30cm long and weighed 11kgs.

British and Japanese mortars weigh in second, either three or two inches in calibre, weigh nine or 4.5kgs respectively. Hundreds found.

The third most popularly discovered munition is British and Japanese hand grenades. Hundreds found.

The most commonly found bombs were dropped by Americans - 227kgs. More than 30 found. Nine American 455kg bombs have also been located. The third most common, 'particularly nasty to deal with', says bomb disposal officer Dominic Brittain, are the Japanese 50kg white phosphorous bombs, which, when detonated release a chemical which ignites with the air, 'burning right through you'. The device has been banned by the Geneva Convention. Fewer than 10 found.

The discovery of sea mines is rarest. The British laid the most, 455kg mines, from 1939-1941. American and Australian planes also dropped sea mines. Forty found.