The world's largest weapons fair ends today in London and has been the source of a heated debate among Christian protest groups.

The biannual Defence and Security Equipment International (DSEI) exhibition has run from 15-18 September at London's ExCel arena. Self-proclaimed "the world's largest land, sea and air defence and security exhibition," the fair has been the target of an extensive anti-arms trade campaign including several Christian groups.

"I believe this will be one of the next great causes of the church," Andy Flannagan from Christians on the Left told Christian Today.

"The generations that follow us will look back and say 'How did you stay silent while this was going on underneath your noses?'"

The fair featured around 1,500 exhibitors from around the world displaying weapons ranging from rifles and tanks to fighter jets and battleships. However those invited included countries with concerning human rights records, the Campaign Against the Arms Trade (CAAT) said.

"Our main concern is that DSEI issue invitations to countries which are known to be human rights violators," said Pat Gaffney from Pax Christi, an international Catholic peace movement.

"We had Pakistan, Saudi Arabia and Columbia invited to the conference (to name just a few)."

The event was sponsored by the Government department UK Trade & Investment's Defence & Security Organisation (UKTI DSO). Michael Fallon, the secretary of state for defence, spoke at the event opening.

Fallon highlighted the rising security threats the world is seeing including an increasingly aggressive Russia, the rise of ISIS and terrorist attacks in Paris.

"These threats to our security and prosperity underline the need not just for strong armed forces but for the best capability," he said.

However Flannagan said it was ignorant to assume the weapons were only sold to "the good guys."

"Recent history shows, weapons have a way of finding their way into the hands of the those who want them most," he said.

"And they generally aren't the people you want to have them."

Proponents of the DSEI point out that the arms trade creates a large number of jobs and boost the UK's trade and economy.

The DSEI brings together "senior international trade and military experts from across the entire supply chain in an optimal business environment," the event website said.

However Gaffney said jobs which are military related were often technological and engineering jobs which could easily be converted into jobs in the renewable energy sector. This, she suggested, would be a more valuable use of those skills and would mean the jobs weren't lost.

Flannagan went further. Those who argue that the arms trade is beneficial for jobs could "make the same argument for drug dealing, lap dancing and prostitution."

"People are more than economic units," he said. "This is what happens when capitalism trumps morality because money is the only bottom line."