Currently on display at London’s Excel Conference and Exhibition Centre are more ways to kill people than you can imagine: tactical sniper rifles from the United Arab Emirates’ Tawazun Advanced Defense Systems, medium-calibre mortars from India’s Ordnance Factories Board, optical sights for grenade launchers from Bulgaria’s Opticoelectron Group. And there’s the less lethal, too, like the CS gas made by NonLethal Technologies of Pennsylvania. 'Sure it’ll make you tear up,' a company representative said. 'But it won’t kill you.' He might have added: 'usually'.

The Defence and Security Equipment International trade show, which began on Tuesday and finished tomorrow, bills itself as the largest in the world. It brings in some 30,000 visitors from arms manufacturers, governments, militaries, police forces and coast guards around the world. Contingents of high-ranking Botswanan soldiers mingle with South Korean defence ministry officials; Barbadian coast guard captains rub shoulders with Americans from Lockheed Martin. Russia’s participation has attracted particular attention because of its continued exports to Assad’s government in Syria. There was no sign at the Russian pavilion of the Grad rockets familiar to the people of Hama and Homs, just brochures for robotics and radio components. Pairs of men disappear behind frosted glass doors into temporary meeting rooms to close deals. Very little actual buying happens on the floor. Most of it is prearranged, but DSEI is somewhere for business partners to get together and industry members to network. Bulgarians talk to Israelis; a German military technology magazine hands out Pilsner and pretzels.

But the star of the show is meant to be the UK. The British pavilion is massive, decked out in Union Jacks and featuring everything from BAE Systems' amphibious vehicles to Rolls-Royce jet engines to the wares of Varivane Industries, a Wiltshire-based producer of furniture for submarines and aircraft carriers. AEI Systems of Ascot makes 84mm recoilless rifles, 30mm 'gas operated, electrically primed revolver type cannons', and a variety of other guns that can be mounted on aircraft, boats, vehicles or fired from the ground. Most are sold as parts to BAE Systems, but, according to Paul Knott, AEI’s technical and operations director, they can just as easily be sold separately and their products are perfect for countries in the Middle East and East Asia. 'We’re a cheap solution, compared to the big boys.'

With an atrophied manufacturing sector and widening trade deficit, the government has been keen to promote defence exports. In recent years, the prime minister has taken trips to Egypt, Saudi Arabia, Burma and elsewhere to push BAE Systems and other British arms firms. The UK Trade and Investment Defence and Security Organisation is a major sponsor of DSEI. Foreign delegations are escorted through the convention centre by members of the Armed Forces. Sergeant Paul Tarpey of the Royal Artillery, on loan to UKTI, stood at Raytheon’s pavilion patiently explaining the value of the Boomerang III, a ‘state-of-the-art shooter detection’ device.

On Tuesday, the defence secretary, Philip Hammond, walked the halls, examining missiles and munitions before he delivered a speech to a crowd of men in suits and camouflage. ‘This exhibition is an excellent example of the opportunities that we create when government and industry work together, hand-in-hand,’ he said, flanked by German armoured personnel carriers. The countries UKTI invited this year include Bahrain, which has killed more than 100 people putting down the ongoing uprising there, Kazakhstan, where police killed 12 striking oil workers in 2011, and India, which regularly imposes military curfews in Kashmir. ‘We are not ashamed of promoting responsible defence exports,’ Hammond said.