Europe’s biggest arms fair begins in London’s Docklands on Tuesday with 35,000 delegates and exhibitors expected to descend on the Excel centre for the controversial biennial trade show, which has become a focus for protestors.

At least 116 people have been arrested for offences including aggravated trespass and obstruction of the highway in the past week near the convention centre, but regardless of their opposition, the DSEI event has increased in size by 7%, helped by the unwavering support of British cabinet ministers and senior officials.

On Sunday, about 200 protesters demonstrated for the seventh consecutive day outside the exhibition centre and blocked one of the nearby roads, prompting officers from the Metropolitan police to surround them.

A Met spokesperson said: “While the Metropolitan police service always aims to work with organisers to facilitate the right to protests, we also have a duty to minimise disruption so that other members of the public and local community can go about their day-to-day lives.”

Liz Truss, the international trade secretary, and Ben Wallace, the defence secretary, are both due to speak at the exhibition, while 68 international delegations – including Saudi Arabia and Israel – have been invited to view products and services from 1,700 suppliers.

At a reception ahead of the four-day event, Fleur Thomas, head of exports for the Ministry of Defence, underlined the significance of DSEI for the UK. “Whatever the next few days or weeks or months may bring” in terms of Brexit, Thomas said “the future for our defence sector is a very bright one”.

Campaigners, however, accuse the government of putting in a disproportionate effort to support the arms industry. Andrew Smith, from Campaign Against the Arms Trade, said “DSEI simply could not happen on this scale without the political support from ministers.

“Estimates we have seen suggest 50,000 UK jobs are dependent on arms exports, representing about 0.2% of the British workforce”. Last year, British arms sales rose to a record £14bn – with 80% of exports going to the Middle East, the Gulf nations who represent the most important buyers at the event.

A British Royal Navy frigate, the HMS Argyll, will dock by the Excel centre, where a demonstration of “autonomous naval drones” is planned on Tuesday, while the Royal Air Force intends to showcase the latest prototype Tempest stealth aircraft, part of a £2bn development programme for an aircraft not expected to enter service before 2035.

Wallace may also make a long awaited announcement as to who has won the £1.25bn contract to build the Type 31e frigates, with a consortium led by one British firm Babcock, owner of the Rosyth dockyard, the favourite to see off rival bids from BAE Systems and Germany’s Atlas Elektronik.

A total of 32 Israeli companies are amongst the international exhibitors, including Elbit Systems, whose portfolio includes systems for military aircraft, drones, armed remote control boats, and land vehicles.

The event’s promotion brochure describes Elbit’s technology as “battle-proven”; also on sale are its Skylark and Hermes drone systems, which it has previously described as “the backbone of the Israel Defense Forces’ (IDF’s) UAS [Unmanned Aerial Systems] force.”

Eight of the military delegations invited are from what the UK Foreign Office classifies as “human rights priority countries”. They include Saudi Arabia and Israel, but also Bangladesh, Colombia, Egypt, Pakistan and Uzbekistan. Earlier this week it emerged a Hong Kong delegation was no longer planning to attend.

Organisers Clarion Events have been restricting access of human rights groups – and some journalists. Amnesty International was refused permission to visit on Friday, following a meeting with Clarion, although the company said it ensured all goods exhibited complied with UK law.

Staffers at human rights groups had hoped to monitor the exhibition stands to see if they complied with international humanitarian law. Two companies were thrown out in 2013 after it emerged they were illegally marketing shackles and electric shock weapons, and following the intervention of Green MP Caroline Lucas.

Amnesty also released a report to coincide with the event, accusing the buoyant arms industry of “outsourcing responsibility” for human rights violations, by allowing governments to decide for them whether to permit arms sales.

The campaign group had asked 22 major international arms exporters what human rights due diligence they independently conducted, but only eight replied.

One of those that did was BAE Systems, Britain’s biggest arms maker and a major supplier of military aircraft to Saudi Arabia, which is embroiled in the Yemen civil war. Scores of civilians have been killed in air strikes by the Saudi-led coalition – and UK arms exports to the country were ruled illegal by the court of appeal in June because the British government had not properly assessed if military targeting was compliant with international law.

When BAE was asked by Amnesty whether it had conducted any human rights due diligence of its own relating to the Saudi Arabia, the company said its activities there were “subject to UK government approval and oversight”.

Patrick Wilcken, Arms Control Researcher at Amnesty International, said: “Defence giants are washing their hands of their responsibilities by arguing that, once their goods are shipped, they no longer have any control over how they are used. This argument doesn’t stand up, legally or ethically.”