Amnesty International have accused the “Big Four” international accounting firms of acting in “bad faith” after they took out newspaper adverts in Hong Kong saying they were “opposed” to the former British colony’s pro-democracy movement.

The human rights group joined sharp criticism of the extraordinary move by Ernst & Young, PwC, Deloitte and KPMG to publicly state their opposition to the Occupy Central movement calling for electoral reform in Hong Kong, which the corporations described as a threat to the rule of law.

Tens of thousands of Hong Kong residents took to the streets today for the annual 1 July demonstration to mark the surrender of the territory to Chinese control in 1997, in what organisers said they hoped would be the biggest challenge to Communist Party rule in a decade. As many as 500,000 demonstrators - some singing a Cantonese version of “Can you hear the people sing?” from the musical Les Misérables - were expected to take part days after nearly 800,000 people voted in an online “referendum” organised by Occupy Central calling for full democracy.

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Protesters are incensed that a promise to introduce universal suffrage to Hong Kong by 2017, made by China as part of its agreement with Britain, is being tweaked in an attempt ensure that only candidates from a Beijing-approved list can stand for the post of the city’s leader or chief executive. A policy document released by Beijing made it clear that Hong Kong only enjoyed autonomy at its behest and such freedoms were not enshrined.

The audit firms, who between them had global revenues last year of £66.3bn and employ more than 700,000 people worldwide, joined the fray by placing adverts in three Chinese-language newspapers criticising Occupy Central, which has suggested it will stage a sit-in to block traffic in Hong Kong’s business district as part of its campaign.

The advert said: “We hereby announce that we are opposed to this movement, and are concerned that ‘Occupy Central’ would have negative and long-lasting impact on the rule of law, the society and the economy of Hong Kong. We hope that the disagreements could be resolved through negotiation and dialogue instead.”

Shape Created with Sketch. In pictures: Hong Kong's 1 July demonstration 2014 Show all 8 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. In pictures: Hong Kong's 1 July demonstration 2014 1/8 Hong Kong's 1 July demonstration 2014 Participants hold up placards as hundreds of thousands take part in a pro-democracy rally seeking greater democracy in Hong Kong on July 1, 2014 as frustration grows over the influence of Beijing on the city. 2/8 Hong Kong's 1 July demonstration 2014 Tens of thousands of Hong Kong residents took to the streets for the annual 1 July demonstration to mark the surrender of the territory to Chinese control in 1997, in what organisers said they hoped would be the biggest challenge to Communist Party rule in a decade. 3/8 Hong Kong's 1 July demonstration 2014 Policemen block a street in the central district during the rally for greater democracy in Hong Kong on July 1, 2014 as frustration grows over the influence of Beijing on the city. 4/8 Hong Kong's 1 July demonstration 2014 Protesters hold up tablet computers showing an image of Hong Kong's Chief Executive Leung Chun-ying, with a black band similar to that of a funeral altar photo 5/8 Hong Kong's 1 July demonstration 2014 A member of a Falun Dafa band relaxes before the pro-democracy rally in Hong Kong on July 1, 2014 6/8 Hong Kong's 1 July demonstration 2014 Protesters get their umbrellas out when it starts to rain during the pro-democracy rally 7/8 Hong Kong's 1 July demonstration 2014 Animal rights campaigners join the hundreds of thousands of demonstrators seeking greater democracy in Hong Kong on July 1, 2014 8/8 Hong Kong's 1 July demonstration 2014 Hundreds of thousands of participants continue to march until late the evening. July 1 is traditionally a day of protest in Hong Kong and also marks the anniversary of the handover from Britain to China in 1997, under a "one country, two systems" agreement. 1/8 Hong Kong's 1 July demonstration 2014 Participants hold up placards as hundreds of thousands take part in a pro-democracy rally seeking greater democracy in Hong Kong on July 1, 2014 as frustration grows over the influence of Beijing on the city. 2/8 Hong Kong's 1 July demonstration 2014 Tens of thousands of Hong Kong residents took to the streets for the annual 1 July demonstration to mark the surrender of the territory to Chinese control in 1997, in what organisers said they hoped would be the biggest challenge to Communist Party rule in a decade. 3/8 Hong Kong's 1 July demonstration 2014 Policemen block a street in the central district during the rally for greater democracy in Hong Kong on July 1, 2014 as frustration grows over the influence of Beijing on the city. 4/8 Hong Kong's 1 July demonstration 2014 Protesters hold up tablet computers showing an image of Hong Kong's Chief Executive Leung Chun-ying, with a black band similar to that of a funeral altar photo 5/8 Hong Kong's 1 July demonstration 2014 A member of a Falun Dafa band relaxes before the pro-democracy rally in Hong Kong on July 1, 2014 6/8 Hong Kong's 1 July demonstration 2014 Protesters get their umbrellas out when it starts to rain during the pro-democracy rally 7/8 Hong Kong's 1 July demonstration 2014 Animal rights campaigners join the hundreds of thousands of demonstrators seeking greater democracy in Hong Kong on July 1, 2014 8/8 Hong Kong's 1 July demonstration 2014 Hundreds of thousands of participants continue to march until late the evening. July 1 is traditionally a day of protest in Hong Kong and also marks the anniversary of the handover from Britain to China in 1997, under a "one country, two systems" agreement.

The statement, which suggested corporations might leave Hong Kong because of such a demonstration, has been condemned by campaigners and academics for opposing protest and appearing to side with Beijing’s agenda for the semi-autonomous city of 7.2m inhabitants. PwC and Ernst & Young both have their global headquarters in Britain and between them the Big Four audit 99 per cent of the companies in the FTSE 100.

Mabel Au, director of Amnesty International Hong Kong, told The Independent: “Amnesty considers the advert an act done in bad faith and it’s capable of contributing to violations of the human rights of those looking to exercise their rights to freedom of expression and peaceful assembly. Business considerations do not take precedence over human rights.”

The accountancy firms have been heavily criticised in Britain for their role in helping corporate clients reduce their tax exposure using complex avoidance schemes.

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The House of Commons public accounts committee last year said the companies were actively marketing schemes which they calculated stood only a 50 per cent chance of being deemed lawful if challenged in court. The firms rejected the criticisms saying they were legally obliged to ensure their clients’ tax affairs were as efficient as possible.

Richard Murphy, founder of the Tax Justice Network, said: “These companies have shown by placing these adverts the world they live in: one in which protest is seen as a threat to business and therefore to be opposed. In the meantime, their work continues to reduce the tax income of democratically elected governments.”

Concern about the adverts, which were reportedly placed without the knowledge of the Big Four’s global headquarters, has even reached within the companies themselves.

Employees this week took out their own advert in an anti-Beijing paper saying the statement did not reflect their views. The advert in the Apple Daily read: “Boss, your statement does not represent our stance.”

All four companies said they had nothing to add to their statement when contacted by The Independent.